Model Engine Maker

Engines => From Kits/Castings => Topic started by: Jo on November 30, 2014, 09:04:30 AM

Title: 1802 Bell Crank Engine
Post by: Jo on November 30, 2014, 09:04:30 AM
This will probably be the earliest engine I will attempt to build, and I was lucky enough to find some details of the original engine:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/2HPbellcrankengine.jpg)

"The 1802 Bell crank engine is a very compact form of Mr Watt's double rotative engine which was arranged by Mr Murdock and Mr Southern, for steam-engines of small power, to enable them to be placed within a less space than Mr Watt's original construction, and also that they may be set up in any workshop or apartment of a manufacturey, without requiring a particular building for the engine. For this purpose they contrived to support one part of the engine by another"

Anthony Mount designed the model and published it in Engineering in Miniature. I have not seen the original model as Anthony was talked into selling it  :hellno: and later had to make himself a second:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/boultonWattBellcrank-S1.jpg)

Clearly it was not a very popular model engine as the original casting run was only 10 casting sets and they took nearly 10 years to sell  :shrug:. There has been at least one subsequent casting run but they were unable to get the quality necessary for the Cast Iron components and later ones have bronze flywheels and cam ring  :ShakeHead:. This is one of those original 10 casting sets :whoohoo:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8356.jpg)

As casting sets go it has lots of challenging parts which could account for so few people wanting to build one. If I say it is unlike any other steam engine I have ever built you will understand why it has been taking up space on my dinning table for a couple of weeks now  :naughty:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on November 30, 2014, 10:00:05 AM
 :headscratch: It is a fascinating little engine to watch run:

https://www.youtube.com/watch?v=_HrecmErhKQ

As is traditional I will be modifying mine  ;)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: moerman on November 30, 2014, 10:15:29 AM
Jo, that is indeed fascinating. Your description makes it sound as if this casting is a rare vintage product. Is it?

Wout
Title: Re: 1802 Bell Crank Engine
Post by: ths on November 30, 2014, 10:38:48 AM
That is an interesting motion to watch, and I'm glad that tradition will be upheld. So, what are you going to do? Hugh.
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on November 30, 2014, 10:39:59 AM
And I though you said this one had gone back into storage :headscratch: good to see it out though.

The castings can still be bought though with the GM parts, not much of a problem as the flywheel is painted and its only the bare edge of the cam ring that would look wrong
Title: Re: 1802 Bell Crank Engine
Post by: Jo on November 30, 2014, 11:30:50 AM
And I though you said this one had gone back into storage :headscratch: good to see it out though.

It had as the dining table was getting a little busy and I was expecting visitors, still being good but not long now  :LittleDevil:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: steamer on November 30, 2014, 12:02:29 PM
Nice!    Can't wait for the build!


Dave

Title: Re: 1802 Bell Crank Engine
Post by: philjoe5 on November 30, 2014, 01:38:37 PM
That's a new engine to me.  In some ways it resembles the James Coombes Table engine with the long connecting rod arms/crosshead guide and crossbar arrangement.  But instead of connecting that to the connecting rod and journal it goes through the bell crank mechanism.  This will be an interesting build and I'll be following along :popcorn:

Cheers,
Phil
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on November 30, 2014, 01:44:40 PM
So Jo will one of your modifications be the correctly shaped cam wheel or will you stay with AM's round one. This would be one advantage to having teh gunmetal casting as you could squash it a bit ;)
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on November 30, 2014, 01:48:40 PM
A very interesting engine for sure. Its nice to know the history of the castings as well.

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on November 30, 2014, 01:54:12 PM
Hey Guys  8) pleased your are all interested. Jason I am not sure what to do with the cam wheel the instruction for machining it are a bit sketchy and as you say I cannot bend my Cast Iron one.

Now I am not sure if Anthony did what is called poetic license or just got it wrong  :( If you look at the original patent drawing you will see that the bell crank does not have a tail but Anthony's does. The bigger engines like the one in the London Science Museum does have this second power take off on the bell cranks:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/01010003.jpg)

But she is a bigger engine and has a very sexy governor  :Love:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/01010004.jpg)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: sco on November 30, 2014, 03:12:46 PM
This is looking a really interesting engine to build Jo - and a proper challenge even for your skills ;-)

Simon.
Title: Re: 1802 Bell Crank Engine
Post by: arnoldb on November 30, 2014, 03:26:53 PM
A very interesting engine indeed.  Looking forward to your build Jo  :ThumbsUp:

Kind regards, Arnold
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on November 30, 2014, 03:58:58 PM
But are you making the 1802 one or the 1810 one from the science museum, can't really add sexy features from a later engine. Also how complete is that Science museum engine can't see how the belt to drive the governor would work on that square shaft :ShakeHead:

AM certainly had to make some bits up as he went along with only an etching to go by he would not have had all the details and who is to say the original engraver got it right. There are also the compromises that need to be made to keep the costs of castings down so some detail may have been left off.

J
Title: Re: 1802 Bell Crank Engine
Post by: Jo on November 30, 2014, 04:09:33 PM
Jason, I don't know how I have confused you  :headscratch: as I said at the beginning I am making this engine:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/2HPbellcrankengine.jpg)

I am not adding the tails on the bell cranks and I am not adding a governor, they were only fitted to the larger engines. I am going to try to bring her back closer to the design in the original patent for the 4 horses power engine ;)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on November 30, 2014, 04:21:16 PM
Thats OK, I thought the temptation of a Governor may have been too much for you, good to see you are resisting.

Some quite nice drawings here (http://collectionsonline.nmsi.ac.uk/browser.php?m=objects&kv=50963&i=107732)
Title: Re: 1802 Bell Crank Engine
Post by: philjoe5 on November 30, 2014, 04:25:28 PM
Since the Bell crank design was patented in 1802 and I believe the James Coombes Table engine came later I assume Coombes took that vertical crosshead guide arrangement and connected it straight to a journal - crankpin.  Both engines were designed to give a small footprint.  I wonder which design was favored at the time?? 

Cheers,
Phil
Title: Re: 1802 Bell Crank Engine
Post by: Dave Otto on November 30, 2014, 04:39:15 PM
Interesting project Jo,

What purpose to the tails serve?

Dave
Title: Re: 1802 Bell Crank Engine
Post by: Jo on November 30, 2014, 05:01:40 PM
Hi Phil, The later table engines designs are head and shoulders above this early engine:

This Bell Crank engine is a condensing engine and is fitted with Murdock's long "D" slide valve which is driven by the eccentric on the crankshaft (side of the flywheel) Ports with flat faces were cast at each end of the cylinder keeping the steam passages in and out of the cylinder as short as possible. The D valve stretches between the ports for the whole length of the cylinder and is flat on the side next to the ports and semi circular on its back. The exhaust passage was cast into the whole length of the valve to carry the steam away to the condenser.

As a result the engines had poor thermodynamics because the exhaust steam inside the valve passage was being heated by the incoming fresh steam. And the other problem was keeping the packing round the semi circular back tight  :(

Dave: I thought I had a drawing somewhere of those tails being used to drive the paddles on a stern wheeler but I currently can't find it.

Jo

P.S. In case anyone did not know William Murdock with Mathew Murray were Boulton & Watt's "chief engineers". Murray's short valves were a much better design  ;)
Title: Re: 1802 Bell Crank Engine
Post by: Dan Rowe on November 30, 2014, 05:11:19 PM
Hi Jo, Murdock invented the slide valve which was the long form. I have been very interested in this form of valve because the very early Shay locomotives used a long slide valve but it was called the double D valve on a Shay because it had two separate valves but it is still essentially the same as the long slide valve.

Dan

Edit Murdock's slide valve is British Patent number 2340 of the year 1799.
Title: Re: 1802 Bell Crank Engine
Post by: Jo on November 30, 2014, 06:01:12 PM
Hi Dan, yes what you are talking about is the modification that came in for the improving the Murdock valves:

The middle section of the valve was replaced by a rod or rods joining the two ends, the result was a much lighter weight valve. It also had the advantage that it was no longer necessary to plane the entire length of the valve chest the only two areas needing planning were under the faces themselves. They were still a devil to get to seal  :ShakeHead:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on November 30, 2014, 07:29:12 PM
 :( These castings are all over the place, The base is under height on one end, over on the other. It is too wide but if I mill both sides down to get the right width the sides will be about 1mm thick and as it is gunmetal it will end up a bit soft :ShakeHead:

Did I mention anything about the square nuts and bolts? Well if you are making one of these then please don't follow the article which says you need 80 pairs and whoever originally had this engine had kitted themselves up to make all of these. But for the life of me I can't find anything like that number. There are a number of what I think should be studs that could have been square bolts on the original but I am not sure that there is the clearance for the heads to turn (unless they are clearance holes) and you know how much I like my studs  ;)

The material that has been supplied is BMS but I do like stainless fasteners on my engines these days... do I really want to start milling round stainless into square to make the fasteners  :thinking:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on November 30, 2014, 07:35:54 PM
As its gunmetal why not slice it down the middle and solder back together and add a bit of height where required at the same time. I did at one time quite fancys making one of these without castings, the base casting is only a box with a few attachments so easy enough to fabricate.

As we said the other day I think its nearer a total of 80 fasteners not 80 each of nuts and bolts
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on November 30, 2014, 08:32:23 PM
Back to casting sizes again, on the height have you allowed for the thickness of the brass beading that needs to be added to the lower section?

Also are you using the 1.875" width or the width over the beading of 1.937" when you say its too wide?
Title: Re: 1802 Bell Crank Engine
Post by: Johnb on November 30, 2014, 10:22:42 PM
A nice old engine. I'm looking forward to following the build. I remember the later one in the Science Museum. A good looking engine.
Title: Re: 1802 Bell Crank Engine
Post by: smfr on November 30, 2014, 11:15:18 PM
Good to see you back on steam, Jo  ;D I will follow along with interest.

Simon
Title: Re: 1802 Bell Crank Engine
Post by: Captain Jerry on December 01, 2014, 12:36:05 AM
This will be an interesting engine build to follow.  Lots of detail and a different geometry.  The cam ring and follower are a real departure from the usual eccentric. The castings and the Anthony Mount model show a round cam ring and I cannot see any benefit to a "squashed" one as shown on the patent engraving. I would bet that the patent engraving is a distortion by the engraver and not as actually designed.  the long D valve will also be a challenge, I would think.

Jerry
Title: Re: 1802 Bell Crank Engine
Post by: Alan Haisley on December 01, 2014, 03:09:02 AM
This looks like another to learn a lot from.  :popcornsmall:

Alan
Title: Re: 1802 Bell Crank Engine
Post by: Jack B on December 01, 2014, 03:26:59 AM
Hi Jo: I read all the postings on your engine. I am going to follow along and wish you the best of luck. I think it will involved some interesting machining.  Jack
Title: Re: 1802 Bell Crank Engine
Post by: fumopuc on December 01, 2014, 05:46:49 AM
Hi Jo, I like the kinematics of this engine. Good to see you starting an other steam engine build again.
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on December 01, 2014, 08:04:11 AM
This looks to be yet another interesting build to follow along  :ThumbsUp:  :ThumbsUp: I'll be there  :popcorn:  :DrinkPint:
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 01, 2014, 12:51:03 PM
As its gunmetal why not slice it down the middle and solder back together and add a bit of height where required at the same time.

Not a good idea as Bottom cover which slides within the sides of the Cistern is also over sized and if you reduced the width of the cistern it would fall over the outside. No it is another of those cases of identifying the mating surfaces and making them match each other and hopefully getting equal material where needed.

These are the instructions for the nuts and bolts given in the drawings, they miss out all the other sizes you also need to make :-\

Jo

Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 01, 2014, 01:26:53 PM
Well you could do the same with the condenser & its cover, how wide is the actual casting and whats the wall thickness
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 01, 2014, 02:31:35 PM
The bottom cover goes on the bottom of the cylinder.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 01, 2014, 04:14:46 PM
my mistake. In that case just cut the two legs off the bottom cylinder cover and resolder. If the legs are too wide then by the time the cover has been turned to dia you may not get the nuts in to the two fixings that are on centre line
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 01, 2014, 04:39:15 PM
Or as it is a casting, for which no measurements are critical, find a measurement that all the castings will work for  ;).

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 01, 2014, 07:55:46 PM
The first thing we need is a reference, the easiest being the base but because both sides of the casting has a draft angle it is necessary to pack the two sides parallel. Not forgetting that the casting is hollow so longer pieces of steel have been used either side to spread the pressure of the vice:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8378.jpg)

It was next clamped onto a rather large angle plate and the two ends cut flat and square. Using the reference base and the same end it was now possible to square up the casting, machine the top to height (or below height as the casting allowed :-\) mill the tops of the stands deep inside the cistern for the condenser and to take the outside brackets to height.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8379.jpg)

At the far end on the top you may just about be able to see that I have also taken out the two corners this is to add some ears as part of the next stage. I also milled the insides of the part just under the cylinder to take the bottom cover.

Nearly half way on this bit  :)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: philjoe5 on December 02, 2014, 12:06:59 AM
Jo,
Being quite the novice at machining castings I have a question.  Since the base of the base is going to be your reference plane, machining it seems critical to me.  How do you align the casting in the vise to ensure you'll have enough material on the other sides to machine those surfaces true?

Cheers,
Phil
Title: Re: 1802 Bell Crank Engine
Post by: Maryak on December 02, 2014, 01:38:19 AM
Hi Phil,

Normally with any casting one fiddles about with it to see if it is suitable to be machined, (i.e. its not too small and the observable surfaces have no blow holes etc.). Next a suitable datum is determined and marked on the casting. The casting is set up for machining using the datum line/points for reference.

In Jo's case where the 1st cut is to mill a base a second line would be offset from the datum and the casting set up to this line then milled to the line. Once the base is machined the casting is returned to the marking off table and everything re-measured from this new datum.

Well that's my way; and my working with castings has only been with 12":1'

HTH

Best Regards
Bob
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 02, 2014, 07:53:36 AM
Hi Phil,

Yes as Bob says I had to fiddle around with it balance this bit being over sized and that bit under. My final decision was actually where someone had already had an attempt at squaring up the bottom it was within 0.5mm of where it needed to be as a starting point.

So squared up with a level it was faced down by the 0.5mm. There was still a couple of slumps but they will be underneath so will not be seen. Having removed 2mm on the length to get both ends square it is now 1mm short and the area around the cistern where the beading is supposed to go will be lower than the drawing says  :shrug:

That beading :headscratch: the kit came with what I expected a reel of D shaped beading that is normally put on using soft solder and some G clamps as I did on my Clayton Cab. But the drawing shows something that looks more like a piece of brass that has had its edge rounded

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 02, 2014, 10:30:38 AM
Don't think they make the 1/2 round beading down to 1/16" so its out with the file to round off the side of some flat strip then fit that to the top of the casting, thats why I queried if you had allowed for that strip when you said the sides were low as it effectively adds 1/16" to them.

Did not think these castings were supplied with any bar stock, is that something teh previous owner had stockpiled for te project
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 02, 2014, 11:19:53 AM
Did not think these castings were supplied with any bar stock, is that something the previous owner had stockpiled for the project

You are right these casting sets do not include bar stock but when I picked these up second hand the previous owner had added them  ;D


You will appreciate that as a modified second hand set they were very expensive (£90 :disappointed:) but not as bad as another set of castings that have promised to come along to tempt me on Saturday :slap:   

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 02, 2014, 01:33:58 PM
Anything that might tempt me ::) though I expect they won't make it past his pickup point :(

Having said that I think I enjoy the fabrication more than working from castings so can see me going more down that route unless its something very desirable.

J
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 02, 2014, 02:42:39 PM
:hellno:

They are castings, best you avoid them  ;)

It would be nice to get a set of Otto Langen patterns into the Foundary then my retirement casting sets will be ready and waiting for me :embarassed:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 02, 2014, 03:44:24 PM
Don't think I'll get to do any on the Otto until over xmas, thats if I don't work with a client being away for 3 weeks its tempting to get on in the empty house.

Best you get on with those BB1 patterns to go with them :LittleDevil:
Title: Re: 1802 Bell Crank Engine
Post by: kvom on December 02, 2014, 04:06:16 PM
:hellno:

They are castings, best you avoid them  ;)

It would be nice to get a set of Otto Langen patterns into the Foundary then my retirement casting sets will be ready and waiting for me :embarassed:

Jo

The trick is to figure out how long you're going to live in order to get the right number of casting sets.   ::)
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 02, 2014, 04:40:34 PM
Best you get on with those BB1 patterns to go with them :LittleDevil:

That was the plan: have them finished to go into the foundry with the batch at the beginning of the new year  :whoohoo:


The trick is to figure out how long you're going to live in order to get the right number of casting sets.   ::)

I added it up the other day: stationary engines is about 10 years (11 years if I feel sorry for the one this Saturday), another 8 years of large model vehicles. But of course: I will have to buy more casting sets if I can convince work to give me early retirement  :pinkelephant:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 03, 2014, 05:40:09 PM
Four feet machined  ;D

They were nasty  :ShakeHead: They have been finished at 17.5mm long instead of the 16mm because if I took them any thinner the sides of the U-section would have had to come down to 1.6mm rather than the 2.4mm that I decided to leave them at.

To machine them I first machined found the level with the top of the U bracket and machined them to the 17.5mm width, to the top and machined the 9.53mm height, then raised the cutter to the 8mm to provide how far they stick out the sides. Then changing to a 3.2mm cutter found the same depth as cut with the previous cutter and then slowly faced the indie of one of the arms of the U to the required 2.4mm wide. that gave me a zero, then moving over 9.26mm machined the other inside face before stroking the bottom down to my chosen depth of 3.2mm which will be the face that is used to bolt the engine down with  ;).

That is it for this evening as I am off to buy some come-in-handies from my club's White Elephant sale  :naughty:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: steam guy willy on December 03, 2014, 07:16:13 PM
Jo, this may be the earliest engine that you are making, however,    better late than never !! I will be following this this with interest,  am still making the S&P with much fettling to do ,(should have adheared to the drawings) Good luck with the new engine.
Regards
William

semper rectam quote.........
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 04, 2014, 07:44:15 AM
So what elephants followed you home?  :pinkelephant:
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 04, 2014, 08:15:36 AM
 :embarassed:  Only a few odds and ends: A rotary table that I think someone might be hoping to pinch off me, a few gas torch bits, some milling cutters, usual tat  :shrug:

However never let it be said that I have to buy every casting that presents itself to me: I turned down two this morning that I need :ShakeHead:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on December 04, 2014, 09:59:35 AM

However never let it be said that I have to buy every casting that presents itself to me: I turned down two this morning that I need :ShakeHead:

Jo

Jo what is the world coming to you will not sleep well with such an imbalance in the force  :stir:

good build log as is your normal practice
Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 04, 2014, 12:08:30 PM
Thanks Stuart  ;D

You are right I can see such thoughts driving me to  :DrinkPint: if I am not careful. Hopefully Saturday will bring things back to normal  :mischief:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 04, 2014, 01:22:15 PM
Bet you only turned them down as it would have required more moths than you were willing to let fly :LittleDevil:
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 05, 2014, 06:08:03 PM
The cistern needs a couple of little ears added to it onto which the crankshaft bearings will mount. These were machined out of a piece of 6.35mm square brass. First machined from the side to get a curved front:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8397.jpg)

Then on the top to give a square corner:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8398.jpg)

Drill a couple of holes and tap them for a pair of brass screws and the ears can be secured into place:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8399.jpg)

Sufficiently to then silver solder them permanently:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8400.jpg)

The condenser took the opportunity of joining us in the workshop while I waited for the cistern to cool. So first machine the top, using the central hole as the reference, once it had been skimmed, the sides were taken to size (of course one dimension was undersize again :-\)

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8396.jpg)

The underside was also machined then a quick check for the fit:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8402.jpg)

 :naughty: I have been sent photos of castings  :slap:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on December 06, 2014, 12:07:33 AM
Nice start on the base Jo! Certainly an interesting engine too!!

Bill
Title: Re: 1802 Bell Crank Engine
Post by: philjoe5 on December 06, 2014, 02:53:30 AM
Jo,
Just so I'm on board here....are the sides of the condenser supposed to meet the sides of the base?

Cheers,
Phil
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 06, 2014, 07:14:33 AM
Thanks Bill  :ThumbsUp:

Hi Phil  :) When running the Condenser will get hot so you want minimal contact between it and the sides of the cistern so that the heat is transferred into the water in the cistern and not the body of the cistern. You can just about see the gap round the condenser on the full sized engine in this photo

I have just found out that the piece of brass that came with the casting set for the top of the condenser is under size so I will have to reduce the width of the condenser to suit  :ShakeHead:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: philjoe5 on December 06, 2014, 05:54:05 PM
Thanks Jo.  I'm not familiar with a cistern - condenser style engine but it's starting to become clear.

Cheers,
Phil
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 10, 2014, 07:44:57 PM
The pump started out as a big bronze casting.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8415.jpg)

It seems tempting on a casting like this to hold it by the big end and turn up the bottom  but the larger end needs to be machined first and left over size. This then gives the flat surface to go back against the chuck and provides a repeatable surface to hold by

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8416.jpg)

Now we have something to hold it by it can be turned around, sadly it is too big to fit in a collet chuck so has to be protected by an aluminium shim from a drink can and held in a chuck. The casting is over length and all of the extra length is in the stem so it is important to use the base of the top as the reference and turn everything relative to that. As you can see there was a fair bit of extra stem so whilst it was still at 22.23mm diameter I parted off the spare to add to my come in handy drawer.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8417.jpg)
Having put that little extra bit in a safe place the stem was taken to diameter and the bolting flange turned:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8418.jpg)

Before going any further we need to think about drilling the bolting holes. If we wait until we have turned up the top of the pump we will have nothing solid to hold the casting by and we are likely to crush the bronze  if we try. So off to a mill and coordinate drill the holes (you could also use a rotary table )

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8420.jpg)

We can now start to think about turning the top of the air pump so first boring it to depth  (1.6mm short of the length of the casting). Then opening the centre up to give the top of the pump chamber:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8422.jpg)

Before completing the inside it is time to do the outside, so first turn to diameter then set up the top beading using a parting off tool.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8423.jpg)

The outside follows a 7.5 degree angle which must run up to the centre of the top beading. The use of marker pen provides an easy indication of where the angle has progressed to:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8425.jpg)

Once it meets the top bead it is time to change to a more suitable tool and cut the 0.8mm deep part between the two beads Then using a 1.6mm diameter external cutter the beading was touched up:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8426.jpg)

The trickier bit was cutting the internal angle past the top of the pump chamber:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8427.jpg)

This was achieved using a ground down broken milling cutter mounted in a offset square tool clamp:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8428.jpg)

Jo


Title: Re: 1802 Bell Crank Engine
Post by: Tennessee Whiskey on December 10, 2014, 07:51:49 PM
The machining is up to your above par standards, but, the photos look great 😍. New camera?

Big E
Title: Re: 1802 Bell Crank Engine
Post by: Dave Otto on December 10, 2014, 07:52:11 PM
Nice job Jo!

You sure made short work of that one.

Dave
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 12, 2014, 04:19:11 PM
Hi Eric & Dave thanks for following along.

The air pump spindle is machined from a piece of 4.76mm diameter stainless which had to be turned down to 3.18mm for over 50mm of its length. The piston itself is more of a bucket:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8429.jpg)

Which then has to have the air holes drilled into it:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8430.jpg)

The last bits to add are the valves which are 0.8mm thick brass discs (one has a 8BA tail) which should have 0.15mm thick leather glued to them but I did not have any leather under 2mm thick so chose to use a sheet of 1mm thick rubber gasket material (The sealing layer goes on the other side of the bottom valve):

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8432.jpg)

Getting the valve into the bottom of the air pump is most easily done if you balance the valve on a piece of rod the diameter of the bore as it is inserted. Finally the brass nut is tightened up to keep the bottom valve from coming free. Both of the valves are free moving and seem to provide an adequate seal:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8433.jpg)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on December 12, 2014, 04:33:43 PM
Nice work there Jo those pics are worth a thousand words

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Bjorn_B on December 12, 2014, 04:51:52 PM
Very interesting, been thinking hard about building this one. Might have a go at it next winter.
Title: Re: 1802 Bell Crank Engine
Post by: steamer on December 12, 2014, 07:23:23 PM
Looking Great Jo!

Dave
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on December 12, 2014, 08:53:28 PM
Still following along  :popcorn:  :DrinkPint: I'm not sure that I have understood the assembly  :headscratch:

Is the brass disc with the threaded boss that is standing on the rubber sheet in the second to last picture the one with the nut on the end in the last picture?

Beautiful work as ever  :ThumbsUp:  :ThumbsUp:
Title: Re: 1802 Bell Crank Engine
Post by: Bjorn_B on December 12, 2014, 09:41:41 PM
Jo might correct me here but It seems you are corrct, it's the bottom check valve of the vacuum pump, there is another valve on top of the piston

Still following along  :popcorn:  :DrinkPint: I'm not sure that I have understood the assembly  :headscratch:

Is the brass disc with the threaded boss that is standing on the rubber sheet in the second to last picture the one with the nut on the end in the last picture?

Beautiful work as ever  :ThumbsUp:  :ThumbsUp:
Title: Re: 1802 Bell Crank Engine
Post by: Johnb on December 12, 2014, 11:12:06 PM
Looking good Jo
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on December 13, 2014, 12:35:56 AM
Nicely done as always Jo. Sure isn't a lot of material left from that big bronze casting but it looks like it machined well.

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 13, 2014, 08:16:19 AM
Thanks Guys.

Good morning Roger, Bjorn is correct on top of the piston is a second valve which is just under the collar that was formed when I had that long turning exercise yesterday.

Before I start I thought you might find the Cylinder castings interesting. Unlike a normal steam engine the cylinder on this engine has an inner and an outer which have to fit tightly to each other as the steam has to travel through the join. The valve surface extends beyond each end of the cylinder making it difficult to mount against a surface plate.

The other parts in the photo are the two covers and the cylinder stand and at the bottom the part that will form the valve "chest".

And a couple of drawing errors, the holes on the top of the cylinder are shown in the wrong place and if you place the studs on the cover where they originally went, then with the much larger AF square nuts there is not enough space to turn the nuts. I will get on to the corrections to the lower cover stud locations later.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 13, 2014, 09:04:58 AM

Unlike a normal steam engine the cylinder on this engine has an inner and an outer which have to fit tightly to each other as the steam has to travel through the join and the valve surface extends beyond each end of the cylinder making it difficult to mount against a surface plate.

Jo is the two part cylinder not just a simplified way of getting the void rather than a one piece casting and with a complicated sand core that would give the same result? Much the same way that a lot of traction engine models use a liner to form the steam jacket around the cylinder. I know the valving is different to the usual slide valve but did not think the two part casting was because of the valving.

J
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 13, 2014, 09:08:08 AM
The two part is to make getting the steam "void" possible whilst providing a reasonable price casting. It has nothing to do with the valve face.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 13, 2014, 04:27:13 PM
The only datum we have on the cylinder is the valve surface so to start with that was faced to give me an appropriate distance to the centre line of the cylinder.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8439.jpg)

The pattern for the casting was not very well aligned or parallel and you can see how far out the end of the valve face is:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8440.jpg)

Anthony suggests mounting the cylinder on the lathe and boring between centres then fly cutting the ends. I must have misunderstood this I cannot see how you can fly cut the ends when the valve face sticks out beyond the top of the cylinder

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8441.jpg)

As my Prazimat only has clamping slots beyond the length of the cylinder I decided no to bore the cylinder on the cross slide but to mount it in a four jaw chuck and to bore it:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8444.jpg)

You can just about see the step on the inside of the bore that aids with the press fit:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8442.jpg)

Anthony's instructions for machining this part leaves a lot to be desired. 

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on December 13, 2014, 05:18:23 PM
Looking good there Jo

I do think that reading the article/book regarding any build ( unless it's you that wrote it ) can lead to confusion , I refer back to my prior posts I think that the written word applies to the fabricated parts before the castings were done hence the bore and fly cut although it could be done with a small fly cutter set to miss the outstand but that would only be true for one end.

You will just have to make a boring/facing head for your mill or search evil bay but then that could let some moths out of your poss 😛
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 13, 2014, 05:37:33 PM
I don't think it could even be done with a boring and facing head. The only way it could be flycut is to reset it on the cross slide at a lower height so the sweep of the tool covered the wide flange at the top but stopped short of the protruding back of the valve face. This kind of defeats the object of doing both at the same time which keeps them at right angles to each other. Though I suppose if it were fioxed to a vertical slide it could be done in one setting but that is not what his photos show

The description is definately based on castings not a fabricated cylinder
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 14, 2014, 11:52:49 AM
A couple of members had mentioned that they do not like the use of the Smileys: If you don't like them if you look under your forum profile you can turn them off.



I have just found out my old friend Brian Marshall who was well known for building historic model Stirling Engines in the SMEE and who I had hoped was going to help identify some nice Stirling engines for me to build is no longer with us  :'(

A couple of Brian's Engines:

(http://i214.photobucket.com/albums/cc12/jothoms/MEX%202012/IMG_2113.jpg)

(http://i214.photobucket.com/albums/cc12/jothoms/MEX%202012/IMG_2112.jpg)

(http://i214.photobucket.com/albums/cc12/jothoms/MEX%202012/IMG_2111.jpg)

(http://i214.photobucket.com/albums/cc12/jothoms/MEX%202012/IMG_2109.jpg)

(http://i214.photobucket.com/albums/cc12/jothoms/MEX%202012/IMG_2108.jpg)

(http://i214.photobucket.com/albums/cc12/jothoms/MEX%202012/IMG_2107.jpg)

(http://i214.photobucket.com/albums/cc12/jothoms/MEX%202012/IMG_2106.jpg)

He was also famous for setting fire to the odd show over the years  ;)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on December 14, 2014, 03:10:49 PM
Sorry to hear that Jo. Thanks for adding the pictures to your post...he was obviously a talented modeler!!

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 14, 2014, 04:31:38 PM
Thanks Bill, it is only now that I realised that I have photographed so many of Brian's models but can't find one of him.

The inner cylinder is a sort of dumbbell shape and it is necessary to first turn up a register on the bit that has to stick out of the chuck:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8445.jpg)

This gives us the necessary surface against which the fixed steady can press, with a little anti-scuffing to help:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8446.jpg)

I tried machining the step on the end of the liner then realised it was still over length:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8447.jpg)

On to a mandrel and turned the two outer surfaces to match the inside of the outer cylinder:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8448.jpg)

As you can see I had left the outer cylinder in the four jaw chuck so it was nice and square for pressing in the liner:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8449.jpg)

It got this far and it stuck solid :-\

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8450.jpg)

So alternative means had to be found to sneak it in the last little bit  :naughty:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8453.jpg)

I might have mentioned that Anthony's article did not give any clues about how to machine the cylinder to shape  :disappointed: So standard practise make it up as I go along, mount on a angle plate, make sure the bore is square to the table:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8455.jpg)

Machine the first side including the step:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8457.jpg)

Then using the first end as a register set up the second side and check the angles before machining:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8458.jpg)

 :-\ Clearly the cylinder end that had been held in the chuck was not as well positioned as I could have hoped and where there is little extra metal on these I have resorted to adding a little JB Weld to build up the edge just in case it proves to be under sized. I could of course reduce the diameter of the flange but lets not tempt fate yet:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8459.jpg)

As you can see the witness line between the inner and outer is hardly visible. And I also had one last day with another old friend today  :-[

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8456.jpg)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on December 14, 2014, 05:06:27 PM
Nice work Jo keeping my eye on this build for future reference , there is always a setup method that you show that may come in useful later.
Your tin of ASP looks about as old as mine ,but looks to be a taller tin , mine is about half as tall and as a screwed top, as to the age of my tin it was my dads and I have a memory of it from when I was about 10 ,57 years ago along with a imp Brown and Sharpe mic. USA made in a wooden box still with the spanner and instruction book it's a odd mic has it does not have a ratchet

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Bjorn_B on December 14, 2014, 05:43:10 PM
Wow, this is is somewhat of a novelty, an S7 bolted to the ceiling  :headscratch:

this is a very interesting read Jo! Will you make the condensor functional? I guess there has to be some sort of water spray injecton apparatus to make that work..
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 15, 2014, 08:48:13 AM
Thanks Stuart  :)

Bjorn I am not planning on running this engine on Steam so not the condenser will not work. The photo problem is normally a "feature" of some of the well known computer products, someone said it was to keep you on your toes :LittleDevil:

I keep looking at the drawings for the cylinder and it did not look right so I ended up redrawing it so that I can understand what is needed. Good job too as otherwise I would be starting this morning by running a milling cutter down either side of the valve chest. And I seem to have an extra casting that I cannot account for  :headscratch:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 15, 2014, 03:29:35 PM
The only part of the cylinder that can give us the true register is the bore, so the cylinder was mounted on an expanding mandrel and squared up:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8460.jpg)

Then tucking an 8mm end mill into the back of the top clamping surface the flange was taken to width:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8461.jpg)

Then the top of the valve surface could be milled at the same setting.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8462.jpg)

As you can see there are more holes in this castings as well as the valve chest being out of line to the main casting so after a bit of a fettle, out with the JB Weld:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8470.jpg)

 :headscratch: What are these unknown castings doing on the dining table.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 15, 2014, 03:45:59 PM
Bottom one has similar mountings to the Eisfeld and a similar name, was talking to Eric about one on friday, may be one of those.

As for the top one they all start looking much the same after a while :embarassed:

EDIT, Bottom is the AM that you mentioned
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 15, 2014, 05:15:35 PM
Jason, The top is an Atom minor. I am still trying to find out what the second is, father Xmas when he dropped in, didn't bring the drawings  :facepalm:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 15, 2014, 06:10:35 PM
He also looks to have forgotten the timing bracket for the MK111, hope you got a discount if its not included :ROFL:

J

PS My edit should have said top engine. I can't quite remember the name of the other but it has "feld" in it somewhere, I thought it was a small Eisfeld as the way the bearer mount wraps around to teh front of the negine is very similar.
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 15, 2014, 06:17:57 PM
Father Xmas doesn't charge for presents  :hellno:

The second he tells me is a 14.3cc Felgiebel

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 16, 2014, 10:14:49 AM
He also looks to have forgotten the timing bracket for the MK111, J

The timing bracket casting often cracks as the original design is not thick enough. Looks like I have some drawing Mods heading my way, hopefully they will include the redesigned timing bracket  :)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 16, 2014, 10:20:54 AM
Thats the one I was looking at at Sandown, got the Fel bit right at least.

So another two 2-strokes with fixed venturis, You need something with a carb so you can play with the throttle next, and a 4 stroke would not be a bad idea :D.
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 16, 2014, 10:32:13 AM
 :embarassed: I am not saying what is on the dining table, only it is a four stroke.

More redesign work I started turning the top cover and something didn't seem right. The packing gland on the cylinder was round and the one on the valve stem oval  :(. A quick check with the Science Museum engine and yes the cylinder one should be oval as well. That was lucky I was just about to machine the top

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 16, 2014, 04:18:27 PM
I've started work on the covers: As normal I start by turning a register on the top cover casting. This can then be used to hold the casting whilst the underside is turned. Not forgetting to also drill and ream the hole for the piston rod so everything is square ;)

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8473.jpg)

Then holding it by the 25.4mm boss it is possible to turn the top and using a D bit for the hole in the centre of the valve gland. (I took this before I turned the under cut on the top of the cover )

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8474.jpg)

Because both the top and bottom covers need the same nick cut out of them I next mounted up the bottom cover/stand and turned the top of that:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8476.jpg)

I first tried mounting the cover in a 5C collet to mill the part out the side but it proved to be too large a diameter so had to mount the cover in the vice, centre it up then use a milling cutter to cut the piece that goes around the valve surface:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8477.jpg)

Then I could do the same for the bottom cover having made sure that the legs were square and holding behind the cover and not on the legs to prevent the gunmetal bending as it does :ShakeHead:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8478.jpg)

This was when I found that milling the top of the cylinder had caused burrs in the location holes  :wallbang: It took a while to get rid of them I did consider mounting the cylinder up and boring the burrs out but using engineers blue I scraped them out :-\

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8480.jpg)

The fit seems ok around the valve chest:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8481.jpg)

There is a slight misalignment between the milled outside edge of the cylinder and the covers that is going to touched up with a file.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 16, 2014, 04:30:49 PM
Its comming along.

Looking at the burrs being thrown up in that picture of you milling the notch in the top cover I think you could do with some sharper cutters, I know GM is soft but a sharp cutter will create a lot less of a burr than that.

J
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 16, 2014, 05:22:07 PM
Looking at the burrs being thrown up in that picture of you milling the notch in the top cover I think you could do with some sharper cutters,

That was a brand new cutter I was using  ;). No the problem was using that nice and wide carbide tipped tool to cut the face in a single cut. Its great on steel, not so great on GM  :disappointed:.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 17, 2014, 12:04:37 PM
The top cover has been drilled and the cylinder tapped for it (for now)

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8483.jpg)

Now the challenge  :rant:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8484.jpg)

With a casting that is 50.1mm across the outside of the feet, you cannot put two mounting screws on a PCD of 25.4mm :toilet_claw:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on December 17, 2014, 12:38:40 PM
It would seem that the casting to small syndrome is alive and well

Is there enough meat to shrink the PDC down a smidge ?

Nice work with the documentation Jo

stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 17, 2014, 01:16:13 PM
You could use bolts from above or a stud and nut above, both easily drilled and tapped from above.

Should the width across the legs not be 1.875" ( 47.63mm ) anyway
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 17, 2014, 01:24:14 PM
Hi Stuart: no the bolt holes are just on the outside of the legs, it would nearly be down the bore on the inside   :facepalm2:

Should the width across the legs not be 1.875" ( 47.63mm ) anyway

The width across the legs should match that of the cistern = 50.1mm

I noticed one of the other finished engines the builder resorted to letting the legs only sit on the inside of the cistern but that looses a lot of strength  :ShakeHead: I might have a plan

Jo
Title: Re: 1802 Bell Crank Engine
Post by: kvom on December 17, 2014, 02:33:25 PM
On the few engines I've made to date, I've been drilling and reaming the piston rod hole with the cover mounted to the cylinder and with the mill spindle centered on the bore.  Have you found that drilling the hole on the lathe presents any issues with it being concentric when later mounted on the cylinder?
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 17, 2014, 03:45:49 PM
I know its a later engine but looking at the one in the science museum there is no way a nut or bolt head would fit on that, unless it were a tee headed bolt. So must be a stud & nut or bolt into tapped hole

(http://s0.geograph.org.uk/geophotos/03/66/27/3662720_11133477.jpg)

Also you mentioned the other day about the shape of the piston gland, the science museum one is oval but looking at the etching of the 1802 that is round. See your first post.



Kvom, like Jo I have always done mine in the lathe, provided you do the hole at the same setting as the short spigot that locates in the cylinder then they will both be concentric
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 17, 2014, 04:27:45 PM
Jason, I do not understand what you are trying to say about the bolts.

Also you mentioned the other day about the shape of the piston gland, the science museum one is oval but looking at the etching of the 1802 that is round. See your first post.

A bit late  :ShakeHead: as you have seen I have already drilled and tapped it to be an oval gland.

Kvon: If you machine the bottom of he cover and the register at the same time as boring for the piston rod on the lathe everything has to be in line. The only way it can get out of line is if the bore of the cylinder is different to the register on the cover  ;).

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 19, 2014, 11:37:34 AM
The cylinder base continues :(

The legs were taken to the correct height:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8485.jpg)

Then the sides, the flange under the cover and the step that goes into the cistern:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8486.jpg)

At least it now fits into the Cistern:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8488.jpg)

But it is still not there. In every casting set there is one piece that is a challenge and clearly for this engine this is it  :rant:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 19, 2014, 11:43:56 AM
And don't think you can sneak in that last photo without a comment on whats in the background :naughty:
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 19, 2014, 12:01:34 PM
 :facepalm: Yes I must repair that apple picker.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 19, 2014, 01:58:01 PM
We are over the peak and heading down hill for this part  :whoohoo:

You can see that the bolting down holes on the two sides come through on the side of the foot  >:(

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8492.jpg)

Which meant that I had to use a Tee slot cutter to give some clearance for the nut to hold the cylinder down  :naughty:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8493.jpg)

Clean up the bottom and make sure everything looks square:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8494.jpg)

And finally check that a square bolt will fit and a nut (once I make the square ones  ;) )

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8496.jpg)

Now to try and sort out that top cover   :-\

Jo

Title: Re: 1802 Bell Crank Engine
Post by: kellswaterri on December 19, 2014, 05:41:26 PM
Hi Jo, have not been doing a lot this past few days,tore shoulder...black ice >:D   working on Coombes ,end in sight, took a few detours on the way...your latest build would seem quite a challenge in machining,it would appear to be a common problem with castings which do not  fit the drawing,the square bolt is a great save, 50 yrs. of working on mechanical devices i have rarely seen it used for this purpose...
                        John
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on December 19, 2014, 07:05:20 PM
That's a good solution to the problem  :ThumbsUp:  :ThumbsUp: Still following along  :DrinkPint: :popcorn:
Title: Re: 1802 Bell Crank Engine
Post by: steam guy willy on December 20, 2014, 04:10:25 PM
Jo, here is a reference to the  Murdoch valve gear from a book in 1911. hope this is of interest
Seasons Greetings
William.
Title: Re: 1802 Bell Crank Engine
Post by: steam guy willy on December 20, 2014, 07:01:16 PM
Jo, further to the last post, it mentions putting the mettalic packing on the D part of the valve to keep it flush against the valve face. Is this apparent in the Science Mus engine ? There is a similar arrangement in the Bridewell engine.
Regards
Willbert
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 23, 2014, 12:02:26 PM
Thanks Wilbert: I can't do packing on the valve so my plan is to very carefully finish the valve to height on some wet and dry, if it goes wrong then the valve cover can always have a little reduction  ;)

There are three pairs of bearing blocks on the B&W the first goes under the cistern and supports the bell crank. And has a turned top to it. As the bottom is too thin it is necessary to leave the metal oversize and turn the two bearing blocks plus enough for the tops, back to back, using a four jaw chuck:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8503.jpg)

Then the blocks are drilled before parting (don't forget to mark the orientation/pairs)  and then machining to the correct height

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8510.jpg)

Finally mill the groove in the middle of the base and then fitting the tops to it:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8511.jpg)

They have been fitted with temporary studs and nuts then they will need to be bored but before that I have two more pairs of bearing blocks to make.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 24, 2014, 05:43:08 PM
More bearing blocks  :wallbang: but these need lots of pieces. So starting from a piece of 25.4mm wide, 6.35mm deep BMS both ends were squared up then one by one pieces of the bearing blocks sliced off. Making sure to identify which side is the reference:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8513.jpg)

Then drill hole at the centre of the curved sections to take 4.76mm diameter rod:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8522.jpg)

Then carefully cut the unwanted section off using a slitting saw. You may be able to see I am using a drill to position the slitting saw so that it cuts exactly to the centre line:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8523.jpg)

Into these slots are silver soldered the dowels to give the correct profile. I had been concerned that the bearing blocks that hang under the cistern and take the weight of the bell crank are only supported by 10BA screws as the others show 6BA and 8BA respectively. However  >:( clearly someone, in amongst the zillions of missing dimensions on these drawings, had not taken into account that nothing bigger than a 3.2mm AF nut/bolt head will actually fit on a piece of 4.76mm dowel,

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8524.jpg)

Thankfully I had not drilled for any of those studs  ;)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 27, 2014, 02:07:22 PM
The pedestal drawing errors  :rant:

Main Bearing Pedestal: The distance between the top studs should be 17.44mm. The 4.76mm thick cover looks horrible next to the 10BA nuts so I have taken it down to the 3.2mm  ;) Where the cap extends down to clamp the bearing it needs to be 12.7mm wide and reach the centre line of the bearing. And as for the 7.94mm bore, the bearings are clearly 9.53mm diameter  :facepalm:.

Crankshaft Bearing Pedestal: fails to show that the cap must go down to the centre line of the bearing. If you make it as shown you will not get the bearings, even split bearings, in place :ShakeHead: No diameter shown for the bore which also needs to be 9.53mm  :-\

Cistern Bearing Pedestal: Distance between studs for the cap needs to be 10.4mm, the bore of the bearing is 6.35mm, which in turn is 6.35mm down from the base of the bearing.

All top studs 10BA unless you want your nuts dangling over the edge  :disappointed:

I have amended the amended crankshaft dimensions to match what the castings can provide for, modified the amended pivot shaft so that it includes a bearing for the bell cranks... It is becoming one of those engines  :facepalm2:

Jo

Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 27, 2014, 04:37:06 PM
Jo on my drawings the main bearings are shown with 6BA studs not 10BA so the thicker plate would look about right.

Crankshaft bearing cap can stay a shown you just need to make the lower part "D" shaped so the bearing drops in
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on December 27, 2014, 04:57:33 PM
Jo, you are making so good progress on this one. As to the drawing errors...are you in contact with the supplier as to making proper updates to them?

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 27, 2014, 05:42:43 PM
Jo on my drawings the main bearings are shown with 6BA studs not 10BA so the thicker plate would look about right.

Yes it shows 6BA studs sitting in the middle of a 4.76mm diameter dowel as hex 6BA nuts are 5.6mm across the corners and square ones are some what larger, as I said dangly nuts are not a very pretty sight :disappointed:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 27, 2014, 06:25:06 PM
Thanks Bill,

My plan is to talk to Andy Clark (Polly Models) who now markets these castings at the Alley Pally show.

Since I Emailed Anthony Mount with the problems we were finding with the Cotswold casting sets of his design, Anthony has chosen not to respond to any of my Emails  :ShakeHead:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on December 27, 2014, 07:11:21 PM
That is too bad about not responding to known issues. One would think a designer would welcome such input in order to improve the marketing success of the model, even if someone else is doing the direct marketing on his behalf.  :headscratch:

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 28, 2014, 12:00:46 PM
Finally, it felt these would never end  :ShakeHead: The pedestals are each screwed together with a couple of washers between the cap and main piece to provide the necessary bearing adjustment later. Then mounted into the milling machine vice using the rear jaw as the reference for all the centre heights. Then find the centre:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8525.jpg)

Drill and ream each at the correct height:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8526.jpg)

Then we can start making the mounting holes on the cistern. These have all been co-coordinate drilled using the same edge we used previously as a reference:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8528.jpg)

There is no position for the bearings for the pivot rod :disappointed: If you use the amended design then the studs will break through into the base of the cistern, if you use the first one they mount into the side walls and allow the bearing blocks to sit on the outside of the cistern.

I have decided that I might choose to epoxy resin down the crankshaft bearings as I am not convinced two 10BA studs are adequate.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 29, 2014, 12:18:52 PM
To provide a change I knocked up the main shafts for the engine. On the original engine the crank extension is square with bearing points cut into it:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8529.jpg)

Then I needed to make some split bearings using my stick of two bits of brass that has been soft soldered together to form a 12.7mm square. Starting with the smallest bearing turn the outside, then ream:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8530.jpg)

Before turning the step in the outside, making sure everything fits before the final parting off:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8531.jpg)

You don't want to turn the outside step before reaming as you will have less solder keeping the two parts together and they could move apart  :disappointed: So bearings underneath:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8532.jpg)

And some bearings on the top:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8533.jpg)

 :o And some wood  :paranoia:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 29, 2014, 04:06:03 PM
The piece of metal for the bell cranks had been guillotined off so none of the sides were true  :ShakeHead: It was also bigger than needed and I could have comfortably cut one crank from each end but decided to look to retain as much as possible of the spare metal I marked out the bell cranks on the metal with a gap of 5mm between them which left a nice piece spare on the end ;D .

Off to the mill: Having put a piece of the brown stuff :paranoia: under the metal I drilled each for the pivots with a 3.2mm drill and an extra one in the centre of the material that is to be cut out.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8535.jpg)

At this point and the thought of having to hacksaw the pieces out I suddenly felt a desire to take this piece to visit my good friend tomorrow :naughty:

That did not stop me starting work on the furniture for the bell cranks: The tie rod that goes across the top and the four pivot pins:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8536.jpg)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: smfr on December 29, 2014, 04:54:32 PM
You're making quick work of this, Jo, and it's good to see it coming together!

Simon
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 29, 2014, 04:55:38 PM
You are making fast progress today.

Handy to have any guillotined sheet a bit larger than needed as it allows the 2-3mm of deformed metal to be machined away.

Are you going to drill & tap the pedestalls for oil cups?
Title: Re: 1802 Bell Crank Engine
Post by: Jo on December 29, 2014, 05:06:18 PM
Thanks Guys  :)


Jason, the Bell crank engine in the science museum doesn't actually have oil cups or even oil dimples so as of yet I have not decided and those top caps are very thin  :noidea:


You will be pleased to know that I am having a day off tomorrow to slow down the progress. And as it is not yet new year I don't have to abide by my new year resolution so if I get introduced to any orphaned casting sets :embarassed:

Jo

Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on December 29, 2014, 05:21:13 PM
Very nice progress Jo. As for that New Year's Resolution...it could always be delayed until 2016  :mischief:

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on December 29, 2014, 05:50:34 PM
Good progress  :ThumbsUp:  :ThumbsUp: At least with my own designs all drawing failures are defiantly (or even definitely) my problem  ::)  :toilet_claw: 
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 01, 2015, 03:26:48 PM
Thanks Guys, I am pleased you are still following along  8)


The plate made friend with Eric's bandsaw which saved me a lot of hacksawing :naughty:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8541.jpg)

The two plates were then bolted together using buttons of the same diameter as the boss, as the holes were all drilled on the DRO they all fitted perfectly in their holes. the piece of wood was counter bored to clear my nuts:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8542.jpg)

Then it was a slow human powered milling away of the pieces, first get it square and cut the length and height:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8543.jpg)

Before turning it to an appropriate angle to cut the leading edge:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8545.jpg)

There is still lots of fettling to do  :-\ but at least I have a full set of the buttons ready to attach in the morning:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8547.jpg)

That's it for today as I have a  :embarassed: very special dinner to cook  :whoohoo:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on January 01, 2015, 05:07:09 PM
That's impressive Jo. Those turned out really nice even before the fettling !! Thanks goodness for band saws...that would have been a lot of hack-sawing!!

Bill
Title: Re: 1802 Bell Crank Engine
Post by: smfr on January 01, 2015, 06:13:27 PM
Those look nice, Jo! Another option might have been to drill some starter holes in the interior voids, and hacksaw them out; would have saved some milling.

It's for parts like these that one really sees the benefits of CNC!

Simon
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on January 01, 2015, 06:44:17 PM
Nice work on the bell cranks  :ThumbsUp:  :ThumbsUp: I hope that the dinner was at least as good  :stir:
Title: Re: 1802 Bell Crank Engine
Post by: fumopuc on January 01, 2015, 07:14:59 PM
Hi Jo, I like these bell cranks.
Title: Re: 1802 Bell Crank Engine
Post by: moerman on January 01, 2015, 07:20:50 PM
Quote
Then it was a slow human powered milling away of the pieces.

What is the matter, Jo, no electricity? I think I would prefer to do human powered hack sawing over human powered milling ...  :ROFL:

Wout
Title: Re: 1802 Bell Crank Engine
Post by: Johnb on January 01, 2015, 10:26:19 PM
They look proper. Nice one Jo.
Title: Re: 1802 Bell Crank Engine
Post by: Jack B on January 02, 2015, 04:05:32 AM
Hi Jo still following . I like the way you cut the two triangles. I don't have CNC so I am always doing some operations like you did. Have a nice New Year .       Jack
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 02, 2015, 07:40:14 AM
Thanks Guys  :)

Time wise I am still not sure if drilling a few pilot holes and joining them with the hacksaw would have  taken more or less time. I still had to wind the mill bed too and fro, :-[ I broke two FC3 cutters which caused a couple of dings that need removing  :disappointed:.

Hopefully get these done today, then we can start the more interesting bits and maybe I should do a family shot as this engine is bigger than you might expect  ;).

Dinner was excellent  :mischief: but what with Xmas I think I need another new year resolution to try to get my weight back where it was :facepalm:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: 90LX_Notch on January 02, 2015, 05:25:26 PM
Well done Jo.

-Bob
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 03, 2015, 01:00:49 PM
Thanks Bob  :ThumbsUp:

Each of the buttons were put in place by making some 3.2mm diameter brass tubes which were slightly over the width of the three pieces of metal together then having put some tenacity no 5 in the joints riveted into place:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8548.jpg)

The buttons were then silver soldered:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8549.jpg)

Then there was a bit of character building to round the edges and clean them up. At least now I have something to hang the more interesting bits on  :naughty:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8551.jpg)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 03, 2015, 01:44:48 PM
Nice work Jo
Nice bit of copper in the background I spy

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 03, 2015, 03:59:21 PM
Thanks Stuart

Nice bit of copper in the background I spy

And some castings  :embarassed:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Dave Otto on January 03, 2015, 04:03:16 PM
Hi Jo

The family shot looks nice :ThumbsUp:

Question; when you riveted the joints together on the bell-cranks did you do anything to maintain joint space; or does the solder just flow where it can?

Dave
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 03, 2015, 04:40:54 PM
Thanks Dave  :).

When I parted off the buttons the finish on one side was not as good as the other but that meant that there was space for the solder to run so that was the side that was joined to the parent metal and had the flux applied  ;)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 04, 2015, 02:32:43 PM
I keep forgetting the condenser  :wallbang: The top was co-ordinated drilled along with the condenser. One to watch here is that the air pump holes are shown as 8BA clearance when the top cover must be tapped 8BA:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8554.jpg)

Then the condenser itself needs to be milled out to allow for the partition with the flap valve to be added:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8555.jpg)

The observant amongst you may have noticed that the air pump is going to come rather close to the cover mounting studs to overcome this Anthony decided that milling two flats on either side would give a bit of additional clearance. A bit but not enough for 4mm A/F Square nuts  :disappointed:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8556.jpg)

I also knocked up the condenser gland:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8557.jpg)

If it was not time to prepare to go back to work  :paranoia: it would be time to start on the fastners  :-\

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 04, 2015, 03:24:37 PM
Jo

Will you please stop with all this profanity with four letter words I am deeply offended with there use


It's the W word that is most offensive

W o r k it's the word in question  :stir:

It brings back some memories from the past like getting up for a six o'clock shift start ,cleaning the car windscreen of frost

Sorry only jesting it's now over 17 year since I stopped doing it

As you posted earlier that engine is a mite larger that I first envisaged , it's comming along just fine

How is your true love coming along ?

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 04, 2015, 03:56:57 PM
Will you please stop with all this profanity with four letter words I am deeply offended with there use

Sorry Stuart, not long now but my attempt to retire this coming year seems to have failed  :rant: All is not lost as the low price of oil meaning that our main customers won't have any money to buy any toys from us so there is likely to be another early retirement opportunity shortly  ;D   

How is your true love coming along ?

On hold at the moment I have to make the cylinder patterns. I had planned to make it over this long holiday but for the first two weeks I felt awful (which is why I haven't been making much  :disappointed:) and the idea of working in the brown stuff didn't make me feel any better.

Once they are done and we have the batch of all the other patterns together they will be off to the foundry. I had planned that the money from my old Myford would fund them but yesterday I found its having to go on a replacement washing machine  :toilet_claw:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on January 04, 2015, 04:27:17 PM
All the other patterns are now done, its just you holding up the batch now  :ShakeHead:

I won't post a picture as it wil make you feel bad ;)

J

PS Cranky is comming along nicely
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 04, 2015, 04:41:26 PM
Jo

glad you are feeling better, ouch on the washing machine but thats the way the cookie crumbles


Stuart
Title: Re: 1802 Bell Crank Engine
Post by: 90LX_Notch on January 04, 2015, 07:01:46 PM
Jo-

Replacement washing machine?  Machine some replacement parts for the old one.

-Bob
Title: Re: 1802 Bell Crank Engine
Post by: zeeprogrammer on January 04, 2015, 11:47:47 PM
I found its having to go on a replacement washing machine

I would be happy to negotiate expanding my duties to clothes washing. My experience is all household dishwashing, spider/bug extermination, retrieval of objects fallen into toilet, some dusting and floor cleaning, and all things related to the procurement and delivery of Chinese food, Indian curry, and pizza. However I am lousy with laundry unless it's all wash-n-dry and nothing that shrinks.

For basic services I am cheap, but special requests comes with a surcharge. Which can also be bartered.  :mischief:

P.S. I don't do windows.  :ShakeHead: My attention seems to drift when I look through them.  :embarassed:

The only reference I could give would kill me.
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 05, 2015, 06:24:37 PM
More missing dimensions: the crank throw is missing  :rant:

And unlike a normal engine you cannot calculate it by looking at the length of the cylinder, the piston/port sizes because the motion goes through the bell crank. So I am guessing at 22.23mm, but I would prefer not to have to guess  >:(.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on January 05, 2015, 06:39:35 PM
Is it worth looking in the letters section of EIM around the time to see if it was raised then or maybe mentioned in a later part of the series?

Or leave them until the rest is made and move the bell cranks by hand and measure the movement needed to get full piston movement less a bit for end clearance.

7/8" does look about right, I know we should not scale off the drawings but it measures the same as the .312+.250+.312 of the crankpin on th esame drawing

J
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 05, 2015, 06:41:15 PM
Jo

This is getting to be all to common with Mr Mounts drawings 

Knowing that the write up is at variance to to the published drawings , but a good number of these must have been made but alas the drawings have not been corrected

Neither is it shown in his books, but I would make a guess with your assumed measurement and the drawing bring in the imperious mode it would be 15/16 but it's only a pure guess 😱

It troubles me greatly that the suppliers are not held to task , because they are not fit for purpose , they just print them off charge us good quality money with no errors contained within or boy would they winge
Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on January 05, 2015, 06:44:22 PM
To be fair Jo's drawings could be quite old, the current ones may have revisions on them.

Jo do you have the actual drawings or are you going by the EIM articles which are what reproduced in the book?

J
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 05, 2015, 06:47:07 PM
Jason

The said measurement is missing in the book also


Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 05, 2015, 06:56:07 PM
For basic services I am cheap, but special requests comes with a surcharge. Which can also be bartered.  :mischief:

Sorry Zee I nearly missed your post  :-[ yours sounds like a wonderful offer but I don't think you were around when I was "discouraged" from making or responding to such comments :shrug: 

I am also trying to only refer to "fasteners" in my threads the future, it makes posting so dull  :disappointed:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 05, 2015, 09:17:01 PM
The length of the cylinder = 82.55, the two cut aways for the covers are each 4mm long, the piston is 15.88mm leaving 58.65mm total available movement.

The bell crank is 88.9 by 106.4 so 4 to 5 ratio.

The cranks throw represents half of the movement of the top of the bell crank, plus we need a bit of gap on either end so allowing for 1.6mm gap either end : (58.65 -3.2)  / 5 *4 = 44.36mm 

Which sounds remarkably like my first guess of 22.23mm throw 8)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 06, 2015, 09:05:19 AM
This is getting to be all to common with Mr Mounts drawings 

Knowing that the write up is at variance to to the published drawings , but a good number of these must have been made but alas the drawings have not been corrected

Stuart to my knowledge very few of these castings sets have ever been sold. The first run was a batch of 10 sets of which Anthony made one, it took Bruce/Andy over a decade to sell those. Since then there was a second batch cast and Anthony made his second engine from these: I could find out from Andy how many sets were cast but I can't see it being a large run.

I understand the drawings for this engine were produced in pamphlet form like the Crosskill - My casting set did not come with one so I am building from the magazine which as we know is normally riddled with drawing errors  :ShakeHead:

Over recent years Anthony has been making ever more challenging to build engines, so whilst an engine like this should be relatively easy to correct some of his later engines as we have seen can be a nightmare. I have another two of his engine casting sets in my collection: both from Cotswold  :toilet_claw:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 06, 2015, 09:56:01 AM
Jo
Well you know my feeling for the Cotswold products so we will leave it at that

You my have guessed from my old English location but I am only 4 miles from the drunken parrot ( my name for Polly for when Jayne answers the phone she says" polly models " well to me it sound like polly wobbles )
Hence the name

Now do not get me wrong but I do commend AM for doing more chalanging designers but with that there needs to be more care taken in the quality of the product castings and drawings else more will reiki de under the bench not finished.

Very few of my projects over well shall we say my daughters age 46 have had perfect drawings and I am ashamed to say I have had to measure the plan ,taking a known measurment to get the scale ,to complete the project , a lot of the older LBSC era ones often say check from job 😱

Anyway enough diversion I am sure you will sort it but I bet a pound to a pinch of snuff it will be a imperil dim

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on January 06, 2015, 10:24:05 AM
I think just about every ME drawing has to some extent errors and ommissions, its just something that we have to get over. I have done three of AM's designs two being enlarged versions where I have to come up with far more dimensions than are shown on the drawings to get the "casting" sizes. The two enlargements were also taken from the book/magazines so more likely to have errors.

The downside of all this moaning about castings/drawings (particularly if you don't have the drawings) and not getting on with the model is that it will discourage people like Anthony from comming up with new designs and the suppliers won't want to risk offering kits so at the end of the day we will all suffer as there will be less new models comming onto the market.

The small batch numbers Jo mentioned should also be taken into account, if a casting is found to be comming out under size and the pattern needs to be reworked that is going to cost money which will have to re recouped in teh cost of subsequent castings. Question is will customers be willing to pay these increased costs on what are already quite expensive castings.

J
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 06, 2015, 11:17:59 AM
The downside of all this moaning about castings/drawings (particularly if you don't have the drawings) and not getting on with the model is that it will discourage people like Anthony from comming up with new designs

Jason, I am documenting the build of my engine and the problems I am finding along with their solutions in case others are interested in making one of their own.

The main thing that is stopping Anthony doing new model engine designs is his Vicar :ShakeHead:.

These castings are not undersized, they are too big, in the case of the cistern it is not possible to reduce the width to that of the drawing and maintain structural strength in the walls :-\

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on January 06, 2015, 11:53:13 AM
Jo, I know you are documenting your build and the issues you are finding with the drawings that you are using but you have not made it very clear to the casual observer that you are not working from the same drawings that a potential purchaser of a set of castings would have which could well put them off. I only knew for sure what drawings you were working from when you posted this morning.

I'm actually of the oppinion that Anthony and also Malcom Stride both left a bit of information out of their magazine drawings to mean that people would have to purchase the drawings particularly in Malcoms case. Which you can't really blame them for.

Undersize, oversize, wrong shape, etc all can really only be cured by reworking the patterns as they are not faults of the casting process.

J
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 06, 2015, 12:46:53 PM
To clarify:

Mine is one of the original casting sets dating from 1993, even if I had the original drawing set that was supplied with them, I have no idea if the original drawings have been updated in the last twenty two years.

I have taken the opportunity to discuss this engine with the designer and specifically asked if there were any problems with the drawings, he was unaware of any in 2011 when we last spoke about it. But then he also had not made one for many years and who remembers the various faults with their own engines once they are finished  :shrug:

I know that Anthony is a man of high moral standards and would not intentionally cheat the his readers out of being able to make a model solely from his articles.

I am continuing to work with these original castings I have no idea if the current castings are made from the same patterns. These castings were supplied by Bruce Engineering who I would have happily recommended to anyone as a casting supplier.

Jo

P.S Bruce is now retired  :whoohoo:
Title: Re: 1802 Bell Crank Engine
Post by: Jim Nic on January 06, 2015, 02:40:40 PM
I am an inexperienced modeller of castings having completed just 1 Stuart 10V and being close to the end of a Polly Models supplied Easton and Anderson Grasshopper from Anthony Mount.  I have found a few errors and omissions in drawings and deficiencies in castings, particularly in the Grasshopper, but have come to regard these as all part of the challenge and have in several cases resorted to fabricating parts in place of supplied castings.  I can't recall a build log involving castings where everything went smoothly without some adjustments and head scratching.  I am in agreement with Jason's sentiment that if we demand a perfect product then it will be unviable commercially and we will have no product at all.  We are, after all, a commercially small market and most of us know how to look after a pound!
In meeting the challenges of modelling I rely heavily on our "Casting Queen" to post build logs such as this one from which I gain not only specific guidance on a particular engine but also pointers on how to deal with castings and shortcomings in drawings in general and also Jason's masterclasses in fabrication. 
So, regardless of the why's and wherefore's, we are where we are and must find ways of dealing with it.
Keep up the good work Jo, I'm following along (lurking?) with interest as always   :ThumbsUp:
Jim
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 06, 2015, 03:23:03 PM
Ok all

One last comment then I will shut up as my comments appear to have offended

It doesn't cost the supplier or originator of the drawings any more for a correct one or one with errors

The castings is another matter

Back to Jo as it her build log

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 10, 2015, 07:53:42 AM
There are three crank arms on this engine, each start off as a piece of rectangular BMS which is drilled and reamed for the centres.  Then each in turn are mounted up on a mandrel:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8559.jpg)

The crank is both offset and tapered so first cut the offset by holding the crank arms from each end and cut off the necessary 1.6 and 2.4mm:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8560.jpg)

Then it is necessary to taper one side. It took me a while to grind up a suitable tool that could do this :disappointed:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8565.jpg)

And as it is a very steep angle you have to mess around trying to get it so that you can use the top slide over the top of the saddle.  :headscratch: I can never understand why they design some lathes such that the top slide handle hits the saddle in this configuration :wallbang:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8566.jpg)

Then it is the normal rounding the two ends using the BCA and a bit of fettling:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8569.jpg)

And yes for the observant amongst you the larger ends of the crank arms are not 15.88 mm diameter  :hellno: They are 12.7 as I decided that made them look more like the original engine's crank arms  ;)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 10, 2015, 08:00:52 AM
Looking good there Jo

What did the crank throw finish up as ?

I need to note it in my notebook ( I mean iMac ) on a normaly unplugged 3tb thunderbolt HDD I use for ME storage ,scans in and WHY

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on January 10, 2015, 08:12:26 AM
Looking good Jo.

One tip for anyone who may have the handle clash problem Jo mentioned is to swing the top slide around the other way so the handwheel is facing away from you and run the lathe in reverse, cutting on the far side of the spindle axis.

J
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 10, 2015, 08:17:53 AM
Hi Stuart, the throw is based on my calculations = 22.23mm  ;)

One tip for anyone who may have the handle clash problem Jo mentioned is to swing the top slide around the other way so the handwheel is facing away from you and run the lathe in reverse, cutting on the far side of the spindle axis.

:hellno: then you would have to reach across the lathe when it is running to put on the cut :ShakeHead:

I was considering turning down the top slide handle to allow it to clear. You may have noticed I had removed the "fingers" from the handle to prevent it hitting the saddle handle.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 10, 2015, 08:26:00 AM
Jo

Noted


Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on January 10, 2015, 08:52:28 AM
But you are reaching over the tailstock end so no safety issues (disengage and lead/feed screws to be sure)

Yes saw you had removed the handles. A nut driver or screwdriver is the screw end is slotted will extend the handwheel to where it can be easily turned.
Title: Re: 1802 Bell Crank Engine
Post by: Dave Otto on January 10, 2015, 03:57:55 PM
The crank arms turned out nice Jo :ThumbsUp:

Dave
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 10, 2015, 04:17:19 PM
Thanks Dave  :).

This engine has bearings with cotters :Love: on both ends of the bell crank rods and the piston rods and on one end of the air pump rod which means ten cotter sets :whoohoo: As the rods are thin I am making them up out of pieces and will silver solder them together after so first up the forked ends:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8577.jpg)

To start I cut eleven pieces of 9.53mm by 4.76mm and milled a 6.35mm slot in the centre. This was done by stepping in 9mm from the end of the piece of material, drilling a hole on the centre line then moving on 15.88mm and drilling another hole. I then swopped over to an odd 3 flute cutter (5.73mm  :headscratch:) knowing that it wouldn't be able to cut a straight or correctly sized slot and roughed out the centre of the slot, before finishing with a 6.35mm end mill to take to the correct width.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8571.jpg)

You will notice as well as my 11 pieces the right size there is also 4 that  >:( sneaked in when I wasn't looking and I discovered after slotting the first one it was 10mm wide not 9.53mm  :facepalm:

Normally at this point I would be looking to chain drill out the cotter slots and do a bit of gentle filing between them but with 22 slots to cut  :disappointed: Sexy has been displaying is remarkable abilities of late and has been trying to seduce me into having a play with him. He is a real wiz with very small milling cutters and I had picked up some 1.6mm diameter cutters specially for him  :Love:

But I decided to try something different again  :naughty: I made myself a 1.6mm thick cutter on the ends (yes luckily I made one on each end  ;) ) of a piece of silver steel and then squared up each of the embryo arm ends on the bed and had a little mill:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8573.jpg)

After 6 I got a bit too confident and the next thing I heard was "ting"  :-[ Luckily I had made that second cutter, all of this it took a while and my nerves were rather shattered by the whole experience but:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8574.jpg)

We are getting there, they still need a bit of filing but that will be done when I fit the cotters to them  ;). I now need some nerve medicine.  :DrinkPint:

Jo

Title: Re: 1802 Bell Crank Engine
Post by: Don1966 on January 10, 2015, 07:47:06 PM
Jo nerves shot or not that was a ingenious idea. The pieces speak for themselves.

Don
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 11, 2015, 01:22:09 PM
Thanks Don  :ThumbsUp: Things should get easier from now on :lolb:

Next each was put in the four jaw and the end turned down:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8576.jpg)

Eleven to do every time  :facepalm:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8579.jpg)

Between the ends is a simple dowel turned to length and in the case of the air pump rods a small ring has been put on the opposite end of the rods:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8582.jpg)

These are now going to be put to one side. Yes I know I still need to silver solder them together and cut off the excess but I might use that to aid the silver soldering to make sure the pair of rods are the same length ;) But for now that spare bit gives me something to hold the ends by when I fit the cotters  :Love: So next up is some cotters and wedges and due to the quantity I think I might be doing them "En block"

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on January 11, 2015, 01:42:00 PM
Had you given any thought to loctite and a pin rather than solder? Would save on cleanup.

All these multiple parts will set you in good stead for when you start those radials ;)
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 11, 2015, 01:45:24 PM
Hi Jason I had had a little think about cheating and using Loctite  :naughty:

:facepalm: I have just looked at the wedge and cotter drawings  :ShakeHead: Missing dimensions, wrong dimensions  :(

The material is 4mm thick if we assume that the wedge is 2.3mm at the narrow end then the cotter needs to be 2.4mm in the middle with 1.6mm for the two hooks, not the 1.6mm high shown on the drawing  :hellno:  The most important measurement is the slot on the cotter which must be 9.53mm wide to fit around the ends of the arms, it matters little what the measurements are either side as long as they are the same.

And no mention of the direction of the taper (it is not shown on the drawing) The taper on the Wedge should be narrow end on the end without the hook. If you do it the other way round  :facepalm2: it won't go in.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on January 11, 2015, 03:10:44 PM
Jo, you have really come a long way in less than a month and a half. These latest parts look as exceptional as the rest. I am beginning to wonder though if anything on the drawings is right :)

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 11, 2015, 03:45:31 PM
Thanks Bill  :)

This is one of Anthony's early engines which was published in Engineering in Min, so he was still learning how to publish designs. His later designs should be better  :headscratch: I think if you tried making the engine in the order that he did in the article you could really get your knickers in a twist but I am intentionally doing the bits that match together so that I can hopefully spot the unintentional features before they become too much of a challenge  :facepalm2:

I have another set of castings  :Love: attracting my attention on the dining table so we need to get this one done in a reasonable time frame and of course I need to be able to have a few new engines to display at the show this coming year so far I only have three ;)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on January 11, 2015, 03:56:50 PM
Well going back to the video of the model on page 1 or 2 of this thread...this one should be a real crown pleaser, it is a fascinating engine for sure. Are you going to be doing machining demo's again also?

Bill
Title: Re: 1802 Bell Crank Engine
Post by: vcutajar on January 11, 2015, 04:02:49 PM
Quote
I need to be able to have a few new engines to display at the show this coming year so far I only have three

Jo, you're killing me.  How do you manage to find all that spare time?

Vince
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 11, 2015, 04:23:29 PM
Are you going to be doing machining demo's again also?

That is the plan: For some reason my club GMES doesn't like to do the same thing two years running  :wallbang: Which is why last year I did the demo under the MEM banner  ;). But they were gobsmacked by how many engines we managed to put on to display so we will be invited back and there might even be another live turning event  :whoohoo:

How do you manage to find all that spare time?

Vince, I don't have any other distractions  :shrug: and every time I try to change the situation all I get is  embarrassed/frustrated and left feeling disappointed so I have decided to give up wasting my time and enjoy myself  :)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: philjoe5 on January 11, 2015, 05:17:39 PM
Jo,
I'm still following along and learning new tricks.  I have one of those round indexable toolbits and I like how you used that in post #170. :ThumbsUp:

Cheers,
Phil
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on January 11, 2015, 07:18:37 PM
Nicely done  :praise2:  :praise2: Do the round insert tools tend to chatter? They have quite a large cutting area  :headscratch:
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 11, 2015, 07:39:00 PM
Thanks guys  8)

Roger: I stepped that in taking 1mm deep cuts on power feel with out any problems. The finish is not as good as I would have got with HSS and it will need a polish, which will come as part of the joining the ends to the rods  ;)

That is a 6mm diameter tool: I have larger ones for use on the Colchester :naughty:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 12, 2015, 08:36:07 PM
Cotters and Wedges  :facepalm: I knew they would be too tempting for him over Xmas I have happily seen nothing of the Workshop Gnome, I even thought I might have exported him with the Myford but no he is still here  :(

I didn't have anything the right size to make the Cotters and Wedge so I chose to recycle some of my come in handies one of those ones with the special brown protective coating that Jasonb appreciates so much ;) So starting from a piece of 4.76mm I first skimmed .4mm off one side then turn it over and putting two different diameter rods (1.6mm and 1.2mm) under the piece skimmed the other side to bring it down to 4mm at the root of the taper:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8585.jpg)

Once the tapers were in place on both the cotter and wedge it was then a case of turning them over and on the cotter cutting a slot and on the wedge just leaving a 1.6mm bead:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8587.jpg)

Check the fit on the low side:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8589.jpg)

And the high:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8590.jpg)

 8) So then we just part them off:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8591.jpg)

Trying to prevent the Workshop Gnome from stealing too many of them  :rant: yes he got some before I could stop him :-\ But as you can see I have plenty of spare material so I cut some more:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8594.jpg)

Now for the fun bit: As you can see I have started fitting the first pair but until I have made the bearing I cannot do the final fit for these and I still need to fix the rods. But whilst they are still separate I can do the first fit on the cotters and wedges  :)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 12, 2015, 08:51:37 PM
Nice work Jo

Have you not tried to bait a  mouse gnome trap with a cotter to see if you can catch him/her if it's female it may be nest building so there may be more on the way :mischief:

Stuart
 
Title: Re: 1802 Bell Crank Engine
Post by: Myrickman on January 12, 2015, 10:46:24 PM
Nice work on the rods and keys Jo. All those little tiny parts....although after the setup is done, it's just making chips. I'm interested in seeing the brasses being made. See if I can pick up any tips. I had wondered if anyone has used a broach to square up the wedge holes. I filed mine this time on the Swan..it was good therapy. Your progress is inspirational.
Title: Re: 1802 Bell Crank Engine
Post by: Dave Otto on January 12, 2015, 11:19:16 PM
Nice work Jo!

I think you must have the shop Gnomes working overtime for you  :lolb:

Dave
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 13, 2015, 07:13:41 AM
Thanks Guys  :)

I am filing the slots I am not sure if a 1.6mm thick broach would last very long, even a commercial one.

Have you not tried to bait a  mouse gnome trap with a cotter to see if you can catch him/her if it's female it may be nest building so there may be more on the way :mischief:

Stuart I am assuming as the Workshop Gnome hasn't (so far) shown any interest in castings he must be male  ;).

Jo
Title: Re: 1802 Bell Crank Engine
Post by: sco on January 13, 2015, 07:42:05 AM
This is a first class effort Jo and your usual quality build log - enjoying following along immensely.

Simon.
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 13, 2015, 08:28:18 AM
Thanks Simon,

How is your McOnie coming on? I am looking forward to you solving all the problems in it for me  :naughty: So that when I make my own one I can add some unique features of own  ;)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: sco on January 13, 2015, 10:35:22 AM
Umm - not been much progress lately - workshop is pretty cold which has ebbed the motivation away coupled with busy at work and got back into flying RC helis - need a kick up the posterior really!

Simon.
Title: Re: 1802 Bell Crank Engine
Post by: Allen Smithee on January 13, 2015, 11:09:08 AM
got back into flying RC helis

Can I interest you in some vintage helis that are surplus in my workshop clearout?

 :mischief:

AS
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 13, 2015, 11:13:10 AM
Can I interest you in some vintage helis that are surplus in my workshop clearout?

 :mischief:

:hellno:

Simon is supposed to be finishing off his McOnie and showing me how to over come all the unintended features in the design  :slap:.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: sco on January 13, 2015, 12:07:30 PM
got back into flying RC helis

Can I interest you in some vintage helis that are surplus in my workshop clearout?

 :mischief:

AS

Thanks, but three is plenty already!
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on January 13, 2015, 01:22:16 PM
I've still got some bits off a Morley Bell 47G,now that is a vintage model heli ;)
Title: Re: 1802 Bell Crank Engine
Post by: Allen Smithee on January 13, 2015, 02:29:26 PM
I've still got some bits off a Morley Bell 47G,now that is a vintage model heli ;)

One of the ones I was talking about is a Morely Bell 47 (with the later "AT" collective head). It was built for a magazine kit review that was (at the request of the manufacturer) never published. Jim lived just down the road from me at the time, but he got rather frosty for over a year afterwards.

Others include a modified Schluter Helistar with piped Enya 60XF, an original 1st-batch Kyosho Concept 30 with float undercart, two Kyosho Concept EPs (one with the Bell jet-ranger body kit) and an Align Trex450XL. Oh yes, And a damaged Microsoft Wallis-type autogyro...

AS
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 13, 2015, 08:07:52 PM
Fitting cotters and wedges :facepalm: this involves lots of filing with ground down needle files...  I'm half way, they are all in the slots  ;).

So time to start on the bearings. They are just turned off my bit of brass that is two bits soft soldered together:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8595.jpg)

The workshop Gnome is still around and tried stealing one of them, I couldn't find it anywhere :rant: So I tried Stuart's suggestion and baited the ground with the two spare cotters and suddenly the missing bearing reappeared  ;D I also recovered the spare cotters  :naughty:

And while I was at it I have parted off five pieces to machine the other halves of the bearings out of:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8596.jpg)

There is not that much left on this engine so I am going to have to get on with those fastners at some point  :( Maybe I need to have another little fondle of those castings on the Dining room table  :mischief:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: philjoe5 on January 13, 2015, 08:14:57 PM
Looking good and congratulations for putting one over on the shop Gnome.  My shop Gnome is a few points ahead of me :'(

Cheers,
Phil
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on January 14, 2015, 12:58:44 AM
Looking good Jo. I really do like those cotters and wedges. That ad a very nice detail to these engines.

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 14, 2015, 08:49:34 PM
 :rant: Not a good night. On looking at the top of the piston rods on the original engine drawing I found that the rods going from the bell crank to the piston cross beam only have these open bearings with cotters and taper on one end. So another Anthony "special"  :Doh: I have designed some replacements  :-\

I then decided to try milling one of the bearing blocks to size using the wrong mill under power feed, the solder was only on one side and the two halves parted company  :(. So I cut another one and will start again another day :)

To make up for it I did a bit of casting fettling on that  :Love: casting set that I have been having dinner with of late, only to get rid of the casting sprue marks you understand. I was a little worried but found the two crank case halves are actually a nice match  :embarassed:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 15, 2015, 07:38:36 AM
Nice work Jo
Still got the  :popcornsmall:

Looks like it's becoming a redraw to get things correct to your standard


Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 16, 2015, 05:31:14 PM
A technical drawing of the new ends  :naughty:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8599.jpg)

Then drill/ream and mill with the 1.6mm slot drill  :insane:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8597.jpg)

Before repeating the same turning exercise as on the original ends. Leaving the bearings to be slotted:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8598.jpg)

So some new ends, which still need to be rounded. and the bearings that need to be fitted once each of the ends have been cut down:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8601.jpg)

And yes the workshop gnome does like those bearings  :ShakeHead:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 17, 2015, 04:54:58 PM
 :( Today I talked to the vendor who sells the castings for this model. I explained to him that there were a few errors and missing dimensions on the drawings. I offered to write/draw up a sheet with all the corrections on it so that he could supply it with his remaining casting sets

And he was not interested  :shrug: He said no one had ever identified any faults in the article or the drawings so why bother  :disappointed:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 17, 2015, 05:24:48 PM
Jo

What can I say but that's a disgusting attitude for a vendor to take , we will have to print up some 98p pound notes to pay them with

I have only found one vendor that welcomed any comments and that was D Hewson I phoned him re a missing dim he pulled up the cad file verified that I was correct and amended it there and then with a thank you

As a different note we have had a builder in to sort out a chimney stack ( yes I know it's Saturday but he wanted pound notes for the job :cheers: ) we got taking and he told me he had just restored his dad's SS 80 Brough pity it was not a SS100 but it's still worth about 60k

Nice work on the build

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Don1966 on January 17, 2015, 06:05:47 PM
:( Today I talked to the vendor who sells the castings for this model. I explained to him that there were a few errors and missing dimensions on the drawings. I offered to write/draw up a sheet with all the corrections on it so that he could supply it with his remaining casting sets

And he was not interested  :shrug: He said no one had ever identified any faults in the article or the drawings so why bother  :disappointed:

Jo
That's a shame Jo, did he know you were a woman? Some men get intimidated by women. They should welcome a correction. I had sent Hemingway a correction on one of there casting and they welcomed it and corrected the drawings.

Don
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 17, 2015, 06:13:31 PM
Don

If Andy did not know he should have gone to spec savers , as I believe Jo was at the ally pally show and the vendor was exhibiting there  :stir:


Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 17, 2015, 06:23:55 PM
Don, yes I was at the show, and Andy knows me and my models very well, if there was any question at the time Eric Offen was standing long side at the time who would have corrected him if he dared insult my engine building  ;)

I think it all comes down to how little he makes from the stationary engine casting sets and how much he makes from the kits to make yourself your own "choo choo"  :paranoia:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 18, 2015, 08:07:26 AM
Jo

Your last paragraph was near enough word for word what I said to Linda

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 18, 2015, 08:25:48 AM
I really shouldn't call them that :LittleDevil: But they are a long way from scale models

I was surprised to see two of these bell crank engines at the show. One was the green one that I have shown pictures of previously and this new one. Annoyingly it was positioned such that photographing it was next to impossible  :rant:

The show was not that good... another to be crossed off the list. The club shows seem to be far exceeding the commercially run shows these days so I might even look to go to Bristol this year.

I think the worst part of yesterday was keeping to my new year resolution and giving back some castings  :paranoia:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 18, 2015, 12:15:55 PM
I needed a break from those rods  :( So I decided to make the sump  :)

It took a lot of brass: I started with a piece of 50mm and had to turn it down to 38.1mm leaving a 40mm collar :facepalm: Three cuts later:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8655.jpg)

By holding it in the three jaws most of the centre was bored out, leaving a cup:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8660.jpg)

But the sump is D shaped so it had to be cut leaving the material up to the centre line. So first centre the blade using a vertical

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8661.jpg)

Offset it half the width of the blade and cut it off:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8662.jpg)

To complete it a plate has to be silver soldered into the back. First it has to have its holes drilled into it and then check where it goes on the cistern... Surprise surprise the holes are not shown on the cistern drawing  :ShakeHead: So go back to the original engine drawing in the patent work out it goes about the same distance below the beading as the beading is thick and using the back plate as a jig drill the holes for the mounting studs:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8666.jpg)

As you may have noticed I am using pieces of steel as packers for drilling. Using wood is not a good idea it is never square or flat  :disappointed: Silver solder the back in place and it is nearly there:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8668.jpg)

It still needs the overflow pipe added but that can wait.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 18, 2015, 12:33:39 PM
Nice work and well explained there Jo


Stuart
Title: Re: 1802 Bell Crank Engine
Post by: steam guy willy on January 18, 2015, 12:48:41 PM
Jo, I have been following this build with interest and have noticed on the drawing that the valve drive 'cam' is more  slightly egg shaped than circular , so is this correct or just a not very carefully drawn drawing ? Just wondering !
regards
William
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 18, 2015, 01:33:10 PM
Thanks Stuart  :ThumbsUp:

You are right William, the original drawing shows a egg shaped cam ring. Ideally it would be an oval allowing for a faster cut off of the steam. If I had made a ring in BMS I could had looked to squash it but this came with a CI ring, so there is not way to flatten it without breaking it.

Between the air pump and the sump is a little water shute  :naughty: Which is provided in plan form on the drawings. It is simple enough to cut this out on the flat but you need to get both curves the same, to do this I drew around one and compared the other side to it:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8670.jpg)

And it will fit here:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8672.jpg)

But I am not going to mount it yet as I want to get the condenser in the right place first then I can decide if it needs shortening before mounting.

Ok back to those rods  :paranoia:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Don1966 on January 18, 2015, 03:24:33 PM
I am really enjoying your fabrication work Jo. That is a nice bit of work.

Don
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on January 18, 2015, 03:43:18 PM
All of these little details really make for a nice looking model Jo. That is a shame about the vendor's response as to drawing errors but you are overcoming the deficiencies in your usual expert fashion :)

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 18, 2015, 04:43:18 PM
Thanks Guys  :) I keep telling myself nearly there  :whoohoo:

To get all the rod ends the same length they were cut off using the slitting saw:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8674.jpg)

Then it was back to getting the bearings, cotters and wedges all fitting nicely. With only 0.2mm of adjustment it had to be carefully done. And it was not without its mishaps: the cotters and wedges fell on the floor a few times and there was a bit of a hunt to find them  :facepalm2: I am sure at one point someone was hissing through his teeth at me as I found the missing parts :ShakeHead:

There are getting closer:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8676.jpg)

There is some end rounding to do and then I can look to join the rods together  ;)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on January 19, 2015, 08:34:16 PM
Still following along and enjoying the fabrication skills  :ThumbsUp:  :ThumbsUp: All these parts are so small  ::)
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 20, 2015, 01:14:16 PM
Thanks Roger  :ThumbsUp:

The never ending rods  :facepalm: The top ends of the piston rods needed their outsides rounding so mounted on an arbour on the BCA I used a milling cutter to form the curve:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8680.jpg)

That just left the rounding of the other ends of the rod ends, which I chose to do by filing:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8681.jpg)

I am right handed so you might have noticed that I have positioned the end that I am filing such that if I slip the file will go along the top of the vice rather than catch on the work  ;)

There is a nice piece of 50mm diameter, 155mm long bar that has sneaked in to join my casting set that keeps saying "I've got a crank in me, I've got a crank in me"  :whoohoo:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on January 20, 2015, 01:17:18 PM
Ignor that bar and look at those bits of wood that have long been saying "I've got a pattern in me"  ;)

I see you are busy at work today
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 20, 2015, 01:18:50 PM
I see you are busy at work today

 ;)
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 21, 2015, 05:23:55 PM
 :headscratch: I've been having a little think about how I am going to machine the valve chest and the D shaped valve and have found another missing feature from the drawings  :facepalm:. Anthony's article talks about having packing grooves in the 5.5mm wide D shaped ends of the valve, they are shown plain on the drawing :ShakeHead:

I can't see how having packing material going round those tight corners on the valve is not going to leak, so as I see it my options are to make some say 1mm wide labyrinth seals (and let them gunge up with muck and cause the seal  :naughty:) or just make the piston a nice lapped fit when it won't need any additional seal.

Thoughts?  :noidea:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on January 21, 2015, 06:04:51 PM
I suppose a couple of shallow V grooves around the curved part of the "D" when its turned and then when you mill the flats also cut matching V grooves into the flat faces. Will have the advantage or reducing the amount of surface that needs to be lapped
Title: Re: 1802 Bell Crank Engine
Post by: steam guy willy on January 22, 2015, 12:06:04 AM
:headscratch: I've been having a little think about how I am going to machine the valve chest and the D shaped valve and have found another missing feature from the drawings  :facepalm:. Anthony's article talks about having packing grooves in the 5.5mm wide D shaped ends of the valve, they are shown plain on the drawing :ShakeHead:

I can't see how having packing material going round those tight corners on the valve is not going to leak, so as I see it my options are to make some say 1mm wide labyrinth seals (and let them gunge up with muck and cause the seal  :naughty:) or just make the piston a nice lapped fit when it won't need any additional seal.

Thoughts?  :noidea:
On fig 6 in the drawings there are two grooves pictured, but these may be just at the curved back of the valve. Perhaps these grooves are what AM was talking about ?
Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 22, 2015, 07:27:32 AM
 :headscratch: I am not sure which set of drawings you are looking at William. The ones in the article don't have figure numbers. This is the drawing of the valve.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: steam guy willy on January 22, 2015, 03:22:52 PM
:headscratch: I am not sure which set of drawings you are looking at William. The ones in the article don't have figure numbers. This is the drawing of the valve.

Jo
Jo, It was the drawing at the beginning of your posts. the the original Bolton and Watt drawing.
Regards ,Willbert.
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 22, 2015, 08:14:45 PM
Jo

I have re-read my book twice and have found AM refers to a close fit then later he refers to graphite packing.

This is what I conclude is that the face is lapped to the port face as normal , the valve back face has a grove in it machined before making the D section and that part is filled with packing not the face and will seal and act as a cushion to assist with holding the valve to the port face

To clear it up packing on the curved part and the flat bit lapped to the cylinder face

Hope I have not put some fog in the channel

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Allen Smithee on January 23, 2015, 12:02:11 AM
the valve back face has a grove in it

Oranges or olives?

AS
Title: Re: 1802 Bell Crank Engine
Post by: ths on January 23, 2015, 01:20:18 AM


Hope I have not put some fog in the channel

Stuart

Nice metaphor! Hugh.
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 23, 2015, 08:27:12 AM
This is what I conclude is that the face is lapped to the port face as normal , the valve back face has a groove in it machined before making the D section and that part is filled with packing not the face and will seal and act as a cushion to assist with holding the valve to the port face

To clear it up packing on the curved part and the flat bit lapped to the cylinder face

:thinking: That sounds like a plan  :ThumbsUp:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 23, 2015, 10:30:54 AM
Jo

My thought was you would not want the packing to pass over a port , it would soon be toast and bi ingested into the cylinder, but it would be ok at the back


Let us know how it pans out

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 23, 2015, 08:04:17 PM
The lifting links and connecting rods are finally done. I chose to Loctite on the ends. To make sure the pairs of rods were identically the same length and square they had bits of bar put through the bearings while it was setting.

The only thing that keeps the air pump lifting links square is the piston rubbing up and down the air pump  :hellno: I had noticed on a couple of these engines that their builder had added an additional guide, I might have to add one myself.

Jo .
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on January 23, 2015, 08:10:25 PM
Coming together now, but that's a lot of bits  :ThumbsUp:  :ThumbsUp:
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 24, 2015, 04:01:30 PM
Thanks Roger  8)

Before heading off and playing with my final casting on the engine I thought I had better do the cross beams. Both of the beams are similar  :headscratch: Something doesn't feel right

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8685.jpg)

As there are two of these although slightly different dimensions it is easiest to do them together so I started by turning the ends for the shoulder and threading the ends:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8687.jpg)

 :o Those huge threads on the end of the piston cross beam will have to go  :disappointed:

Sorry not much progress today, I was in the garden too busy counting all the snowdrops, crocus and seeing if I had my first daffodil coming out  :embarassed:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 25, 2015, 05:02:28 PM
Starting by forming the shallow end by the outsides of the rods the taper was then set using feeler gauges and then turned:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8689.jpg)

Having made two square collets each beam was centred and drilled for their rods:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8691.jpg)

Then off to the BCA to mill the two flats either sides of the rods  :facepalm: And I forgot to take any photo's 'cause someone phoned me during this operation  :disappointed: Then mount on an arbour turn the upper and lower circular parts of the boss and then bring together using a file.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8692.jpg)

Then have a trial fit:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8694.jpg)

 :o things are getting a bit tight. The lifting links are touching the sides of the cylinder flanges. The cranks would hit the rods except that they will swing out of the way as the crank turns to its 90 degrees position. I am not sure if there is going to be enough space either side of the cistern for the pin heads that go through the rod ends so there might be more mods there  :-\

And the air pump rod is in desperate need of a second bearing  :stickpoke:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 25, 2015, 05:38:05 PM
Looking good ther Jo but did I miss a pic on a earlier post when you referred to the beams and split bearings that were not held by nuts?

Or did I imagine it , must keep taking the tablets hang on I take 16 pain killers a day any way plus the age related Bp and statins

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 25, 2015, 05:48:09 PM
Did I miss a pic on a earlier post when you referred to the beams and split bearings that were not held by nuts?

On Anthony's engine which has lifting links with the U shaped ends it would have been correct without nuts but as the top of my rods are solid they must go over the ends of the rods which would require the flange behind the bearing to allow the rod to slide over it to get the split bearings in. The consequence of which was that there would be nothing to prevent the lifting links slipping inwards: so back to plan a, b, c  :shrug:

Then I checked the photo of the original engine and it has little nuts on the end of its shaft :embarassed: so I no longer feel bad

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 25, 2015, 06:39:45 PM
Thanks for the explanation Jo

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 26, 2015, 08:19:33 PM
The condenser still needed its divider and with it a flap valve. The valve is a simple piece of 1.6mm thick bras that has a groove filed on it and a piece of 3.18mm dia brass with a 1.7mm diameter hole through it silver soldered on:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8696.jpg)

The pivot is a second piece of the same brass bar silver soldered together into a tee, threaded 6BA. The partition plate then needs to have a hole drilled in it for the valve mounting and a square hole filed for the water to come through:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8697.jpg)

The weight of the flap will make it close:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8698.jpg)

The partition plate was then soft soldered into place:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8699.jpg)

Not that anyone can see it  :disappointed:

So time for something more interesting: the last casting  :whoohoo:  Start off by taking the valve chest cover to width:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8701.jpg)

Find the centre of one end and using a dial gauge square everything up:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8702.jpg)

Then we can carefully start boring and it is a very long boring job  :lolb:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8705.jpg)

Just check it is all central on the other end  ;)

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8704.jpg)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Dave Otto on January 27, 2015, 01:11:34 AM
Nice work Jo :ThumbsUp: I'm still following along with your work here.

Looks like your lathe uses the same DIN style of chuck mount as my Weiler; only mine has 4 studs!

 :cheers:
Dave
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 31, 2015, 03:56:35 PM
Thanks Dave, it is nice to know someone is still following along  :)

The valve is a really horrible thing to make. It is 16mm diameter with a 6.35mm off set tube between the two ends. Having spent forever turning the valve when it came to drilling the 4.76mm diameter hole the drill wandered  :toilet_claw:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8709.jpg)

The second time I decided to make it out of pieces of stainless steel and drill the tube from both ends before I silver soldered it together and turned the ends to diameter.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8710.jpg)

The is was a case of turning the ends to length and exposing the end of the tube at the bottom:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8711.jpg)

Back to the valve chest and using the bore to clamp the part down the sides were milled flat:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8713.jpg)

Taking it through far enough for the top half to separate:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8714.jpg)

Then the valve could be mounted up and taken to width:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8717.jpg)

The last bit of the valve was drilling and tapping the end 10BA then drilling these horrible, horrible holes at a strange angle in the same end  :ShakeHead:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8718.jpg)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: sco on January 31, 2015, 04:21:36 PM
Still quietly following your progress....

Simon.
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 31, 2015, 04:24:49 PM
Thanks Simon  8)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Tennessee Whiskey on January 31, 2015, 05:01:28 PM
I'm still watching and enjoying,  just didn't want to say anything that could be misunderstood or not appreciated   :shrug:

Big E
Title: Re: 1802 Bell Crank Engine
Post by: Jo on January 31, 2015, 05:08:02 PM
Thanks Big E  8),

Some  :old: people did rather knock all the fun out of posting last year :paranoia:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on January 31, 2015, 06:12:09 PM
That valve assembly looks rather complicated  ::) These things always make me wonder how they were made on the original  :headscratch: Did a craftsman simply do it 'by eye' ?
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on January 31, 2015, 06:49:18 PM
Thanks Big E  8),

Some  :old: people did rather knock all the fun out of posting last year :paranoia:

Jo

Jo
Post as you see fit and enjoy your posting

I have been reading up on that valve and it looks likes it would be fun
Still following along

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on January 31, 2015, 08:12:07 PM
So looks like you have decided to go with no gland packing around the valve then?

J
Title: Re: 1802 Bell Crank Engine
Post by: steam guy willy on February 01, 2015, 01:33:01 AM
That valve assembly looks rather complicated  ::) These things always make me wonder how they were made on the original  :headscratch: Did a craftsman simply do it 'by eye' ?
They just made it up as they went along.......in those days of the forge if things were too short you just heated to white hot and bashed it a few times and if things were rubbing you did the same !! "and on the 1/8 day god made malleable iron !

willbert
Title: Re: 1802 Bell Crank Engine
Post by: Alan Haisley on February 01, 2015, 05:47:30 AM

Jo,

It looks like fabricating the valve is the way to go. Especially given the amount of labor lost trying to cut it from solid. The angle drill in your last photo looks tricky. Was there a constraint that needed the part to stick out that far? I can't really tell from the picture.

Alan
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 01, 2015, 08:25:14 AM
Thanks Guys  :)

Jason, The valve is a nice fit at the moment I still might need to lap it to the valve chest .


Was there a constraint that needed the part to stick out that far? I can't really tell from the picture

Yes, I couldn't get the angle in the milling machine vice as the D shaped end was in the way, that drilling vice has a space under the jaws, the D shaped end was resting on the drill table.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: 90LX_Notch on February 01, 2015, 11:14:47 AM
Jo-

Still following along.  The cross beams came out nicely.  I'm always impressed  when people carve from bar stock a part that looks like a casting.

-Bob
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 01, 2015, 01:19:00 PM
Hi Bob, thanks for following along  :)


The cylinder was squared up and first the holes drilled for the studs, another missing dimension the studs need to be 12.7mm out from the centre. Then I started the ports with a 3.2mm drill:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8719.jpg)

It was a bit long for any of my slot drills so I had to finish off the last little bit with an end mill  :ShakeHead:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8720.jpg)

And of course all the swarf has gone in the gap between the outer and inner cylinder  :facepalm:  Whilst it was all square I quickly tapped the holes:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8721.jpg)

Then mounted up the valve chest and drilled that at the same settings as the cylinder. Then came the horrible bit  :paranoia: having to mount it at 45 degrees and drill and tap into the 1.6mm thick wall. Again no measurements  :( I chose to drill the holes 4.3mm across from the bolting face corner:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8723.jpg)

Then take them out to 7.2mm tapping size for the 5/16 by 40 threaded mounting flanges to fit into. The Flanges are a simple turning exercise with a thread on the end, drilled and tapped for the four mounting studs then once the stud holes are aligned soft soldered to the valve Chest. Finally the valve chest is finished, it has been one of those horrible, horrible, horrible bits to make :disappointed:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8727.jpg)

But then I found this in the garden:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8724.jpg)

Summer is coming  :whoohoo:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Allen Smithee on February 01, 2015, 01:48:40 PM
First tap-in-hole shot of the year - a harbinger of spring according to notradamus...

 8)

AS
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on February 01, 2015, 02:39:35 PM
Jo

Got to agree that valve chest , valve is one  :censored: job to machine but you have prevailed and the parts have emerged from chips and problems

Nice work

BTW The grand children have got me a 5c collet rack for my birthday :cartwheel:

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 01, 2015, 03:33:24 PM
BTW The grand children have got me a 5c collet rack for my birthday :cartwheel:

8)

And if you train them right they can buy you one 5C collet each every birthday and Xmas to build up the collection :whoohoo:.

The valve rod is done  :naughty: Only took three attempts  :facepalm: It is a boring bit of turning so I took no photos. There is not a lot left I am going to have to get on with my studs and nuts  :(

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on February 01, 2015, 04:05:20 PM
Jo

I think that idea would be a no starter for the two of them to do that time would run out  with a DOB of 1947 , well you work it out not enough time to complete the set nice sentiment though

I will see how much Syntners remove from the plastic tomorrow when they sort out the nanny system that shuts down the systems when the battery is low , I know it's the battery but try and tell them.

It's 7 years old but it's the type that needs to programmed into the brain to charge it that alone is £250 fitted let alone the diagnostics

If it's not to bad I will get a few. And work out what I need for next month

Keep that build comming along always somthing to learn

Nice daff btw not got the snowdrops out yet up here we must have a couple of thousand scattered around so it dose look nice with the aconites

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Johnb on February 01, 2015, 04:51:03 PM
Always good to see scary parts come out well.

No daffs here yet
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on February 01, 2015, 06:23:49 PM
Nicely done, 20cm of snow here and still falling  ;)
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 08, 2015, 03:25:12 PM
Thanks Roger, we had 5cm on Tuesday  ;)

:wallbang: More missing dimensions and some of those that are there are wrong  :rant:  And the valve chest has warped  :paranoia:

The two ends of the valve chest have some 2.5mm thick brass covers. The drawings were wrong  :disappointed:, the dimensions for the holes to screw into the top of the valve chest  :facepalm: says 9.9mm PCD way out, that would put them down the 16mm bore of the valve  :ShakeHead::

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8749.jpg)

Sadly I missed the fact that the valve rod hole was in the wrong place too  :facepalm2: Having marked a bit of brass out and drilled it, I then used it as a drilling guide and tapped the 10BA holes:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8747.jpg)

As you can see my stud holes are in the curved part of the casting not dangling off the edge as the drawing would have  :hellno:

Once screwed into place the brass covers are marked with a sharpie and then hand filed to shape:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8748.jpg)

Having fitted the two covers it was time to lap the valve in  :-\

Did I mention the casting had warped  :( it took forever  :disappointed:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8750.jpg)

Now I need to sort out that out of line valve rod hole and design a decent gland that you can actually mount the nuts on to without them dangling over the side. You will recall how much I appreciate dangly nuts  :facepalm2:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on February 08, 2015, 03:45:10 PM
Jo

Nice work and well spotted are you sure he did not mean PDRadius  :stir:

These missing and incorrect dims are now beond a joke , there are some on the polly drawings for my current project but as you found it's a waste of time to report them

Maybe we could have a drawing errata section at least it would be a heads up for a tyro who is looking for a new project

I am now drawing the valve gear in turbo cad ( it's cheap and it runs on a Mac so I am happy) , looks like that's what needs to be done because I am loosing faith in the drawings that are out there   Rant mode off

As to the snow we had about 100mm but it did not last long had to send Linda out to dig me a path to the WS  :stir:

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 08, 2015, 04:28:11 PM
Hi Stuart, I have got to the stage that I expect there to be mistakes  :ShakeHead: Not many more parts to go now, then I will start an engine designed by someone more reliable  ;)

I would prefer that there are new model engines coming on the market for us to build rather than not  :-\ I think we just need to recognise that Anthony's Drawings have not gone through the rigor or engineering review. But one would have expected him now that he is drawing it up in CAD to try putting the bits together in the software   :shrug:

I can't remember when Polly added any more of Anthony's engines to their collection. I think Andy has just given up on them, unlike Bruce who, when he ran the business, appreciated real engines :stickpoke:

But not being interested in corrections to the drawings for what you market is just :censored:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on February 08, 2015, 04:50:22 PM
I have not even got that top cover shown in the book.

The Fenby Corliss was the last of AM's one Bruce Eng added so that is within the last 12-18months. The Garret after that is by Cotswold, he does not knock them out any faster than two a year.

J
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on February 08, 2015, 05:08:36 PM
You are making some nice progress Jo, and not easy parts to make either. Quite amazing, given the errors in the drawings.

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 08, 2015, 06:02:49 PM
Thanks Bill  :)

I have not even got that top cover shown in the book.

The covers are on the same page as the Air Pump but the Bottom cover is labelled Top cover and the bottom labelled the top  :Doh: 

I had forgotten about the Fenby as it was a bit expensive. And now I have someone trying to sell me castings again  :shrug:, trying to get me to break my new years resolution  :hellno:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on February 08, 2015, 06:25:11 PM
I did not think the Fenby would interest you as I think Anthony said there would only be two castings in the set.  :-[

Whats Uncle E been offering you now?
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 08, 2015, 06:44:21 PM
Whats Uncle E been offering you now?

I am trying not to think about them  :embarassed:

I was going to be a good girl this year  :mischief:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on February 08, 2015, 06:48:58 PM

I was going to be a good girl this year  :mischief:

Jo

As in Mummy told me to be good, was I?
Title: Re: 1802 Bell Crank Engine
Post by: Allen Smithee on February 08, 2015, 10:57:05 PM
Whats Uncle E been offering you now?

I am trying not to think about them  :embarassed:

I was going to be a good girl this year  :mischief:

Well he's got to pass all those turbine forgings to *somebody*...

AS
Title: Re: 1802 Bell Crank Engine
Post by: spuddevans on February 09, 2015, 01:32:49 PM
I've nothing constructive to add, just to say that your work is great, and I enjoy following your progress.

Tim
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 09, 2015, 02:30:54 PM
Thanks Tim  :)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 10, 2015, 01:18:53 PM
Not a nice bit  :disappointed: The cam ring is cast Iron and thin, that means only one thing hard bits  :paranoia:

In the original article Anthony reckons that if you mount the ring up in a chuck it will bend  :headscratch: Well other than a few sparks flying and the tool dug in, it did let me face the back. Ok I had to finish the really hard bits on the back with a stone in the Dremel ;) You can see them shining in the photo:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8751.jpg)

then he suggests drilling and tapping the lugs which are the really hard bits  :o I take it back they drilled through ok and I still have an intact tap after tapping the holes.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8752.jpg)

But to keep us on our toes there are no measurements for those holes  :ShakeHead: As you can see I blew up the drawing and marked out the spoke line so that I could guess where to drill them. All this is to enable the next stage which needs the cam ring fastened from behind and mounted on a bit of

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8753.jpg)

 :facepalm2: the brown stuff.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: kvom on February 10, 2015, 02:45:16 PM
Any reason you didn't re-draw it yourself to find the coords?
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 10, 2015, 03:06:00 PM
Hi Kvom,  :)

Anthony recommends aligning the cam on the flywheel with the same enlarged drawing to locate it, so it just seemed logical to mark the holes on the cam using the same technique.  We will see if it works in a little while

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Alan Haisley on February 10, 2015, 04:16:43 PM
Jo,
I just went back and took another look at the castings. Do you have to cut through the spines on the spokes to mount the cam ring?
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 10, 2015, 04:25:15 PM
Hi Alan,

No the cam mounts on the flat back face of the flywheel.

If you have a later casting set be very careful with your cam ring it is made of gunmetal and once it has been machined down to 1.6mm thick it is going to be very flexible  :-\.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on February 10, 2015, 07:27:15 PM
That looks to be a rather difficult bit to machine  ::) it's almost the dimensions of a large piston ring  :headscratch:
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 10, 2015, 08:01:11 PM
You are right Roger it is just like machining piston rings except that it is not part of a larger bar of cast Iron to support it  :(

The piece of brown stuff was bolted onto the face plate and the outside edge (that I had skimmed earlier  ;)) brought true.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8755.jpg)

I then found that one of the mounting Allen screws hit the boring bar as it went round so had to take it off again and move the mounting screw holes. Then having taken an initial cut I found it wasn't turning to equal width  :headscratch: finally I found the offender: in clamping up the brown stuff to the face plate it had crushed and one of the mounting screws was now spacing the ring off the brown stuff so off it came again and tighten up the mounting screws :ShakeHead:

Then it was time to break my favourite Sumitomo boring bar tip when I tried to face off the ends of the screws  :'( It was only over 20 year ago I fitted that tip and  :-[ it wasn't just the first corner that broke  :ShakeHead: it cracked across the screw hole

Did I mention those lugs are as hard as  :censored: Two hours later, slowly turning it at 63 rpm, a cam ring:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8756.jpg)

To finish the inner edge of the mounting surface had to be hand filed to 4.76mm wide and to try to get the lugs even they each had a washer super glued to them as a filing guide:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8759.jpg)

Sorry the pictures are not good, bad light and cast iron everywhere  :shrug: And one of the lugs needed building up with JB Weld to make it the right shape  :-\

Another nasty job done so is it time for some studs  :naughty:  or  :wine1:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on February 10, 2015, 08:14:57 PM
I vote  :drinking-41: :)
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on February 10, 2015, 08:20:04 PM
I thought you may have applied some heat to them as you had already found them to be hard.

Infact did they need to be machined, as its a cast part I would have thought you would have kept the "as cast" surface?
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on February 11, 2015, 07:28:45 AM
Jo

I just knew you would beat it into submission in the end  :drinking-41:

Bet that's why thy are cast in the gummy stuff now


Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 11, 2015, 07:55:41 AM
:embarassed: Yes I decided that :wine1: was much nicer than doing any number of studs last night. I will have to try to be a good girl tonight  :mischief:

Hi Jason I thought about heating treating it but each boss would have had to have the heat focused on it for a while and it did drill very nicely. The problem that caused the broken boring tool was the tail of the screw not the hard bits in the casting.

It could not have been left as cast: The back ring needed to be reduced by 1.6mm to provide the 3.2mm bearing ring  for the "beak" follower. If the bosses were left as cast they would have been twice as thick as the remainder of the ring  :disappointed:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 11, 2015, 08:17:18 PM
I nearly forgot to make the gland for the valve chest cover :facepalm: Starting off with a bit of 16mm diameter the top and bottom of the gland were turned leaving a 4mm spigot under the main part of the gland. Then having super glued them together  :naughty: and fitted them to a 5C collet it was over to the mill and use it to co-ordinate drill for the two studs:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8761.jpg)

Now the tricky bit, filing the hole in the top of the valve chest cover over so that what will be the gland fits allowing free movement of the valve rod:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8763.jpg)

Once it is in line a bit more super glue while the mounting holes are drilled through from the gland. Then it was time to file the gland to shape:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8764.jpg)

The last stage is to silver solder the gland on to the cover. Having given it a little rub with a fiber glass pencil this is what it came out like:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8765.jpg)

Now I need more studs  :(

Jo
Title: Re: 1802 Bell Crank Engine
Post by: steam guy willy on February 12, 2015, 11:41:22 PM
Hi Jo, this is a nameplate i made for a friend 45 years ago!!!! it was made using Letrasett and in those days there was a long row of all the patents from different countries. These were very small and a pointed matchstick was use to transfer them to the brass !. It did work first time though. I have finished the AM S&P at last and a big thank you  for all your drawings and photo's that you posted, it was a great help to construct this otherwise bland set of castings !, I am following your present post and liked the 'Kermit" looking part just completed.
Regards
William.
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 13, 2015, 12:21:09 PM
Thanks Willy but this engine doesn't have any etched name plates on it. If I finish it I will probably use my very expensive (£50  :naughty:)  Taylor Hobson Engraver to machine the plate.

Did I mention drawing features on this engine :disappointed: see if you can spot the error on this one:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/Link.jpg)

 :ShakeHead: I will assume that is supposed to be the between centres measurement, rather than my first thought which was the over all length

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on February 13, 2015, 01:01:21 PM
Jo

It's those infernal measurements that are confounding me  :stir:

Yes I think you are correct , but it does make you wonder


Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 13, 2015, 03:25:11 PM
The link started out as a piece of 5mm square. The two holes were first co-ordinate drilled then it had the two boss heights milled:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8766.jpg)

Over to the lathe and turn up a mandrel for 8BA and yes you are right there is no way a 8BA thread is going to hold this for turning but a little dab of superglue on the back to secure the link onto the mandrel as well does wonders  :naughty:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8768.jpg)

First the thicker boss, then the thinner were turned and at the same time the link is being taken to width, the marker pen helps me keep an eye on where the rear edge of the lathe tool is  ;) The second boss and you can see how the centre is now to thickness and only requires a little rub with a needle file to bring it flat.
 
(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8769.jpg)

The two ends were then filed using buttons and finally the centre section thinned down to 3.2mm wide. This link joins the valve rod to the top of the push rod which is a round bar with a square bit towards the bottom. A piece of 4.76mm square was turned between centres to bring the two ends down to 3.2mm and the 8BA thread cut. Then the square section needed a 1.6mm slot cut in it. This could be started using the same cutter I used for the cotters:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8770.jpg)

But it could only get 1.2mm through  :( but the man in my life came to my rescue and milled the centre of slot through to a length of 2mm  :whoohoo:. He couldn't see what all the fuss was about as far as he was concerned a 1.6mm cutter is huge.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8772.jpg)

So the rod fits in here:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8773.jpg)

It is supported by two brackets but don't follow the measurements on the drawings  :hellno:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Maryak on February 13, 2015, 09:08:23 PM
Thanks Willy but this engine doesn't have any etched name plates on it. If I finish it I will probably use my very expensive (£50  :naughty: )  Taylor Hobson Engraver to machine the plate.

Did I mention drawing features on this engine :disappointed: see if you can spot the error on this one:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/Link.jpg)

 :ShakeHead: I will assume that is supposed to be the between centres measurement, rather than my first thought which was the over all length

Jo

Well the only measurement relating to x is the 0.187" from this I make OAL as 0.563" and CD as 0.375" the 0.437" is IMHO???..............Or this is the worlds worst draftsperson!

Best Regards
Bob
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on February 14, 2015, 12:30:30 AM
World's worse draftsman!!  Looks like he couldn't fit the .437 lines where he intended so just stuck them anywhere handy :)

Nice job though Jo!

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 16, 2015, 07:59:07 PM
 >:( I might have mentioned not following the dimensions on the drawings  :hellno: In the last picture you might have noticed that the valve was in its lowest position and there was not much of a gap above it to the steam inlet flanges  :(

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8773.jpg)

Something was not feeling right  :disappointed: so I started measuring. Working from the cam on the flywheel it provides just shy of 25mm travel, which is reduced to 10mm on the rocker arm. The gap on the end of the valve to the edge of the valve chest is 14.5mm so the gap top and bottom on the valve is 2.5mm:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8803.jpg)

Which means the bottom location of the valve is here:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8801.jpg)

And the top is here:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8802.jpg)

With the hole for the rocker arm firmly behind the steam inlets  :Mad: I think I can find 4mm off the valve spindle to move the shaft down a bit  :-\ I had made a pair of brackets to offset the vertical shaft from the cylinder but clearly I was having a bad day and I spaced the holes over too far  :toilet_claw: So another set of those to make  :(

And before I forget all the joys of this engine the brackets for the rocker shaft has no offset dimensions on it to measure the distance from the mounting holes to the shaft central diameter. Anthony admitted when he made his he got it wrong and had to file a bit off the side of the cylinder  ::) Mine is clear of the cylinder, but does that mean that I will have to extend the two levers?

For some reason I felt the need to abandon the workshop after all that.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on February 16, 2015, 08:07:09 PM
You just have to consider them trial pieces  ;) I have made lots of them  ::)  :headscratch:
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on February 16, 2015, 08:13:47 PM
Roger

I consider things like that comfort food for the workshop gnome, hoping he/she will not pinch the good parts   :stir:


Keep at it Jo you will succeed , have faith , you cannot fail

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on February 16, 2015, 08:22:25 PM
The length of your long forked lever may well be different anyway as you are using a thicker flywheel so wil have to take that into account when making the lever assuming you want to keep the flywheel in the middle of the slot in the base.

J
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 17, 2015, 07:33:28 AM
Thank Guys, this engine is not fun any more  :(

Jason, I don't think that the thickness of the outer rim of the flywheel will make any difference as it is the flat side that faces the cylinder with the cam ring bolted on, the hub is the same width.

I do however think I need to do some engine assembly as I am still not sure on my bodge to fix this  :censored: design. I really need to find the mid point for the cam so that will give me the centre height for the Lever arm, which will indicate if the bracket I made last night has got its holes in the right place, which will show me where the centre of the hole in the push rod should be.  :(

Then I can decide if it is the push rod that needs to be longer, or I can do my original plan of shortening the valve rod or the alternative is that the valve chest cover has the flanges too low  >:( I have noticed that on Anthony's second engine he did not fit the second inlet flange so I have my suspicions of what I am going to find  :wallbang:

So next job: fit the cam to the flywheel  ;)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on February 17, 2015, 08:06:26 AM
But if you keep the same distance from engine to flat face of the flywheel that will move the centreline of the flywheel rim further from the engine and put it out of line with the slot in the base. So either the arm needs shortening or the slot in the base needed to be further away from the engine.

As the cam ring has a 1/2" offset from the flywheel ctr then the midpoint is simply its redius above the cranshaft ctr line = 2.344" to the centre of the 1/16" lip
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 17, 2015, 08:09:37 AM
or I machine 0.9mm off the face of the flywheel. I will decide which way to go once it is mounted up.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 17, 2015, 08:20:48 AM
As the cam ring has a 1/2" offset from the flywheel ctr then the midpoint is simply its redius above the cranshaft ctr line = 59.54mm  to the centre of the 1.6mm  lip

and if you measure down the bearing, up the base block, up the cylinder and the offset to the centre of the shaft on the bracket it measures 62.43mm, so a 2.9mm discrepancy in measurements. Is there any reason for the long shaft to be biased down  :headscratch:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on February 17, 2015, 09:34:46 AM
It may not be that simple as I said, best sketch it in alibre/Cubify to be sure.

An angles arm will give fractionally different movement up and down from its mid point.
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on February 17, 2015, 07:02:45 PM
Remember that the original was essentially made up by a craftsman as he went along  ;) There were no drawings for this engine  ::) parts were just made to fit. AM (?) has tried to put something together but it can only be based on what he has found. You have more than enough skills/talent to work it all out and get it running  :ThumbsUp:  :ThumbsUp: Go for it !!
Title: Re: 1802 Bell Crank Engine
Post by: Johnb on February 17, 2015, 09:39:07 PM
Thank goodness it's not just me that hits problems. You'll get it sorted and no-one will ever know.  :ThumbsUp:
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 18, 2015, 01:31:51 PM
Thanks guys, the next engine I am planning to be based on a well tried and tested design  ;)

A little progress: Finding a location that the Cam ring would fit with all the bosses actually on the spokes was fun  ::) In the end it is off set by 1.6 mm, which I plan to take up with the long arm.

The cam ring has to fit on the flat side of the flywheel which means the side of the flywheel that is tapered must face down to drill the holes, hence the use of parallels under the rim:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8804.jpg)

sadly even with all my fiddling three of the mounting holes came through the sides of the spokes  :disappointed: so once the studs are fitted they will have to be filled with JB Weld.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8805.jpg)

More studs to make  :( I started trying to assemble the engine but until the crankshaft is solid it is wobbling all over the place. So next up was to use Loctite on the small end of the central crank with a piece of dowel through the big end to make sure everything was square:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8806.jpg)

This engine really needs bolting down for assembly but I don't know when the new base will arrive  :( so in the meantime I have been trying to line up the outrigger with the end of the bearings using odd blocks of the brown stuff and coffee stirrers  :-\

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on February 18, 2015, 01:39:36 PM
Very soon if you are good ;) Just the small matter of making a bush to broach tapered keyways then it will be on its way :) then I can kill two birds with one stone.

J
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 18, 2015, 01:55:05 PM
Very soon if you are good ;)

I am being good: I still have not brought any new castings this year and the set of Wallaby castings someone tried tempting me with I have returned to him  ;)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on February 18, 2015, 02:15:15 PM
Jo

I thought young ladies did not always need to be good only careful  :stir:   when doing machining work that is ;-)


I knew you would sort it out and yes a proven design of anything is a very tempting proposition


Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 18, 2015, 02:41:16 PM
I knew you would sort it out and yes a proven design of anything is a very tempting proposition

Its not sorted out yet  :( I am slowly working towards it.


I have noticed another challenge: The extended crankshaft has to be permanently attached to the shorter one perfectly in line while the flywheel is fitted. My first thoughts are Loctite them together held in the lathe and a drill chuck in the tailstock :noidea:

Which means I need to finish off the flywheel shortly.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Stuart on February 18, 2015, 02:52:15 PM
Jo

This engine reminds me of old loco drawings

" assembly may be difficult ". Translated means I have not tried it only drawn it  :censored:

Or

" machining may be difficult " same as above only I have not made it

Or my favourite measure from job  :facepalm:

the funny thing I am drawn to it because of the challenge , maybe because I know it's a problem child

Stuart
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 18, 2015, 02:56:38 PM
the funny thing I am drawn to it because of the challenge , maybe because I know it's a problem child

Stuart

Is that why we choose to build so many of Anthony's engines  :lolb:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on February 18, 2015, 07:31:26 PM
Looks like I may be running out of excuses not to visit :-[
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 18, 2015, 08:10:38 PM
 :naughty:

Ever feel you have done something before  :-\ There are two brackets that hold the vertical shaft away from the cylinder that look like:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8808.jpg)

Anthony has a very strange way of making his which I thought looked very difficult, so this is my way: A strip of 4.76mm brass was put in the vice and the end cut square, then using the same 19mm end mill a cut 4.5mm deep made in the middle of the end:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8775.jpg)

:headscratch: Why is that photo showing a slot drill, I used an end mill to cut that :Doh:

The hole was drilled then it was clamped against a 19mm centre on the BCA and the outside profile milled:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8778.jpg)

A bit of filing using buttons to curve around the bearing hole and the guides have been taken as far as I want for now. For now as I am a little puzzled as to how to fit them the drawing implies screwing and tapping into the top of the valve chest but that will be right on the sealing point of the valve  :thinking:

Moving on.. You will never guess another drawing feature  :facepalm:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8807.jpg)

If you can't read the drawing it says the valve rod should be 35mm long  >:( clearly there is only 25mm from the pivot shaft to the pivot on the shaft. I knocked up a quick lever out of a bit of 1.6mm plate and a turning and silver soldered them together. Then had another check:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8809.jpg)

 :facepalm2: Yes that is better but it changes the entire geometry of the workings, now the valve only moves 7mm rather than 10mm and a bit of jiggery pokery and the top movement of the valve doesn't hit anymore  ;D

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8813.jpg)

What I may not have mentioned is the fitting of the end of the lever to make it smoothly run: don't follow the drawing  :ShakeHead: the end needs to be taken to be 2mm parallel for the width of the driving block.

Soon it will be all over and done :whoohoo:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 19, 2015, 06:19:36 PM
 :( A bit more measuring: On the other end of the rocker shaft fits the lever arm and a bracket that screws onto the side of the cylinder. The lever arm has a 8mm wide boss and the bracket is 4.76mm wide plus a bit to take up the curve round the cylinder.

If you look at the photo you will notice that the centre line of the crankshaft is only 6mm off the wall of the cylinder. The lever arm centre line should be 4mm off the end of the centre line of the crank  so that means the rocker shaft needs extending 2mm. On the other side I need 1.6mm for the width of the bracket so the wider part of the bracket which acts as a bearing will have to go on the other side. Or I do what I have seen on another model and extend the shaft 6mm and have the lever arm off centre on the flywheel  :facepalm2:

The good news is the Lever arm length looks ok  :ThumbsUp: But it points more down than up  :-\

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 20, 2015, 04:16:23 PM
My engine has been given its own piece of wood to sit on  :mischief:

Thank you Jason what can I say  :embarassed:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Don1966 on February 20, 2015, 04:37:44 PM
Nice Jo, and aren't you lucky you don't have to mess with the brown stuff. By the way nice work on the engine and I am still following along.  :praise2:

Don
Title: Re: 1802 Bell Crank Engine
Post by: smfr on February 20, 2015, 04:43:18 PM
That's really starting to look close to done! I'm still following along, Jo!

Simon
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 20, 2015, 05:36:47 PM
Thanks Don and Si, I am so pleased that I don't have to mess around with the brown stuff  :paranoia: it means I can get on and finish this engine  :).

but then there is always the painting to look forward to :facepalm:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on February 20, 2015, 06:23:32 PM
Looking good  :praise2:  :praise2: and still on the dinning room table I see  :)
Title: Re: 1802 Bell Crank Engine
Post by: Maryak on February 20, 2015, 11:20:42 PM
Looking good  :praise2: :praise2: and still on the dinning room table I see  :)

Yes,,,,,,, although I'm starting to wonder if the only thing the dining room table is not used for............ is dining.  ;)

Best Regards
Bob
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 22, 2015, 08:27:49 AM
The Lever arm is very simple just three pieces silver soldered together.

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8818.jpg)

The following end started off with a 1.6mm slot cut in it;

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8823.jpg)

Then having been mounted on the rod it was reshaped to this profile:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8829.jpg)

It drags in places but until the second bracket designed and fitted on the cylinder  :shrug:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8828.jpg)

And yes the shaft is still too short  :ShakeHead:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on February 22, 2015, 01:51:56 PM
Jo, seeing it all fit together and on that nice base really shows how far you have come with this one. Despite all the plan errors, you have overcome and the result is a really fine looking model...a testament to your engineering skills (not to mention persistence) :)

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 22, 2015, 04:03:49 PM
Thanks Bill  :) After todays work there is only that bracket for the valve shaft make according to the drawings.

Today's bit was one I have been putting off, it proved to be a non event. the top edge of the cistern has this beading round it:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8837.jpg)

The original owner had brought for half round beading to fit but that is nothing like what the drawings showed so I started off with a bit of 1.6mm brass plate and cut a strip from the size long enough to do all three of the edges that needed beading. I then took the corners off with a file and tried planning it with a bit of HSS tool steel:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8831.jpg)

It worked and just needed a little tickle with a piece of emery paper to finish it  ;D Then beading then had a curve bent in the end and was fitted round the cistern initially fixed in place with brass 10BA Csk screws

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8832.jpg)

before soft soldering into place

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8835.jpg)

 :facepalm: Those square bolts make the holes look out of line. Speaking of fastnings, I had forgotten those so I actually have lots more bits to make  :(

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Dave Otto on February 22, 2015, 04:12:02 PM
Hi Jo

Still checking in and enjoying your progress on this interesting engine; you are doing a great job especially with all the challenges along the way.

I would think the lever arm would have some bronze shoes to run on the cam ring? seems that the steel on steel sliding fit could cause problems.

Dave
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 22, 2015, 09:00:39 PM
Hi Dave  ;) you will be pleased to know this one is nearly finished then I hope that my Kiwi will have less of the sort of features that I have to over come with this engine. I am of course assuming that it is going to run  :lolb:

The cam ring is Cast Iron not steel so hopefully it will act as a reasonable sliding bearing surface.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 23, 2015, 08:13:59 PM
Last bit  :whoohoo: Anthony's drawing looked like this:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8841.jpg)

To get the lever arm to be in the centre of the crank it can't look like that  :ShakeHead: the offset on the main bearing will have to be on the other side but I will try to keep the same shape as far as I can. So start by finishing off the drawing ;)

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8839.jpg)

An interesting bit to hold to mill, the trick being to drill the holes, mill the cut away across the centre then mill the top and bottom steps, remembering that we all have a set of parallels for use in these steps in the shape of drill shafts. Which I forgot to take a picture of  :ShakeHead:

Fitting the bracket to the cylinder required a couple of trial fits before the curve was correct, then superglued into place while the tapping holes were drilled for the two mounting bolts. Tapped and the bracket holes taken out to clearance and

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_8838.jpg)

Its done as far as the drawings say, thanks for following along, I hope you enjoyed it :drinking-41:

All that is left is studs, nuts and painting to look forward to. I think it will also need a drive pulley and of course there is the pair of inlets ports to think about :)

Jo
-    -    -

P.S. I am now short of a set of castings  :naughty:
Title: Re: 1802 Bell Crank Engine
Post by: spuddevans on February 23, 2015, 08:19:01 PM
I hope you enjoyed it :drinking-41:

I certainly did, Thank you for the journey :AllHailTheKing: :DrinkPint: :DrinkPint: :DrinkPint:


Tim
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on February 23, 2015, 08:24:56 PM
P.S. I am now short of a set of castings  :naughty:

I'm sure another set will come along soon, though knowing you they will be like busses ;)

Are you going to make anything to fill that empty corner of the base? and when does the bricklaying start??

J
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 24, 2015, 07:15:49 AM
Thanks Tim.

Jason, the bricklaying will be part of the engine erection which is likely to be slow and tedious due my entusiasm for fastners and painting.

Thanks to you providing that very nice base I am now at least in a position to be able to true up the crank and check that she goes round and round, or for this engine should I say check she "rocks"  8)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Alan Haisley on February 27, 2015, 02:57:09 PM
Jo,
Thanks ever so much for this build. It is really worthwhile watching problems being analyzed and overcome, even for a model that I will probably never build.
 :jumpingsmileys:
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 27, 2015, 05:37:01 PM
Thanks Alan  :),

I now just wish it was a bit warmer so I could do some of the painting. A few more fasteners  :toilet_claw: and I might even be able to bolt her down and try turning her over.

In the meantime I will have to be content with fondling my new castings  :shrug:

Jo

Title: Re: 1802 Bell Crank Engine
Post by: Dan Rowe on February 27, 2015, 05:45:31 PM
Jo,
I have been reading and enjoying this build and I am waiting for the air test. I just want to see it in action. I have only seen a Murdoch valve in books.

Cheers Dan
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 29, 2015, 01:07:38 PM
The engine Foundation:  I have brought myself some Doll house stencils for doing brick and slabs in 1/12th scale. The idea is that you paint the base in the colour for the mortar, then use spray mount to keep the plastic stencil in place while you grout in the holes:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_9015.jpg)

Initially I filled the slabs level with the stencil but found that leaving it a little bumpy gave them more texture. The bricks are another matter, they need to be filled just level:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_9024.jpg)

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_9025.jpg)

I did the first side yesterday now I need to wait for the second side to dry:

(http://i214.photobucket.com/albums/cc12/jothoms/Boulton%20and%20Watt/IMG_9026.jpg)

Then we can start engine erecting  :whoohoo:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on March 29, 2015, 01:15:29 PM
That stuff has worked rather well, can you put up the link to the supplier for those that have not already seen the video as I can't remember where it was now.

Does this mean you may be tempted to make yourself a dolls house :LittleDevil:
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 29, 2015, 03:24:53 PM
It's better than I expected  ;)

https://www.youtube.com/watch?v=GPmq9k3iCk4

But the doll house will have to wait until I have finished all my model engines/castings sets and sold the workshop :lolb:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: philjoe5 on March 29, 2015, 05:31:47 PM
Jo,
I enjoyed following this build.  The photo documentation was excellent and demonstrated a lot of skills in tackling this project that I had not seen before.  Your attention to the details is admirable.  I'm anxious to see it running

Cheers,
Phil
Title: Re: 1802 Bell Crank Engine
Post by: 90LX_Notch on March 29, 2015, 06:12:29 PM
Jo-

The foundation looks really good.  I can't wait to see the engine sitting on it.

-Bob
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on March 30, 2015, 01:49:35 AM
That's an interesting video and quite a system with great looking results. So what it the mixture applied and how is it colored?

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 30, 2015, 07:56:43 AM
Thanks Bob & Phil  :),

Bill, The mixture is their own concoction, it comes self coloured for various purposes. It has fine sand in it, which makes it interesting to lay and it has some sort of (Acrylic?) chemical base as it goes off rock hard and I suspect is going to be very durable. 

I was looking at buying the mini real bricks and making the sides of the plinth out of those but had concern about getting my rows true and even.  And they are not cheap either  :-\

I have used less than 1/8th of each packet of brick/block powder so I have plenty for any other engines I might want to make so other than the risk of it going off in the packet it looks to be good value for money  ;D.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Marty Feldman on December 29, 2016, 05:07:34 PM
This excellent thread plus a recent kind PM from Jo have lead me to make a start on my Bruce Engineering casting set for the B&W 1802 engine.  The first chips are now coming off the cistern.  It appears that the most recent contribution to the thread was almost two years ago, so it is isn't clear how appropriate it is to resurrect it with questions, but I thought I might send up a trial balloon:  I would be interested in hearing comments on the ratonale for having paired steam inlets to the cylinder, rather than just one.  In one version of the engine model I have seen, the steam-in line is bifurcated with one branch to each of the two inlet flanges.  In another, one of the two inlet flanges is just covered with a blanking plate.

-Marty-
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on December 29, 2016, 07:33:06 PM
I have done a couple of engines with more than one inlet on the casting, often one is more suited to the specific site installation and the other simply blanked off.

I did actually see this engine today when Jo enticed me down to hers
Title: Re: 1802 Bell Crank Engine
Post by: Marty Feldman on December 31, 2016, 01:07:59 AM
Thanks for your sensible sounding comment.  I was afraid that I had missed some tricky essential about steam admission.

-Marty-
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 24, 2019, 04:11:06 PM
Having been told I was not allowed any more castings until I had finished at least the Stuart No 1 and it is going to be another 2 weeks until I can get the specified blue steel I had a look around the workshop for other things to play with, like repairing the workbench  :facepalm: ... when I re-found the Bell Crank Engine.  I had nearly finished it  :thinking: but wasn't there was a couple of tricky/boring bits to go  :noidea:

The first for finishing was the chute from the condenser pump into cistern. It had already been bent up but required the hole made in the side of the pump and joining together. The hole was roughed out using H and finished by hand filing. The two parts were soft soldered and then the joint first fettled and then finished by drawing a scalpel along the solder joint. It did not come out bad  :)

I now need to explore the situation with the rest of the engine. And there are lots of fiddly fixings to make  :toilet_claw:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: AOG on February 24, 2019, 04:41:53 PM
I’m glad you’re working on this again Jo. I remember avidly watching this build when I first got started on this forum. I look forward to seeing it’s completion.

Tony
Title: Re: 1802 Bell Crank Engine
Post by: scc on February 24, 2019, 07:45:48 PM
Thanks for the "brick" info Jo.     I've settled in for this engine :popcorn:             Terry
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 28, 2019, 09:45:54 AM
 :rant: I remember why I got annoyed with this engine: The Square nuts and bolts do not fit the engine as described in the drawings  :ShakeHead: And most of the time they look much too big  :facepalm2:

At this point I reviewed my pics of other models to find no one not even Anthony did not use square nuts on his engine  :hellno:


So I am going back to what is  found on the  original Bell Crank Engine and doing a mixture of hex and square  :noidea:

Jo

Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on February 28, 2019, 11:11:59 AM
They do look a bit big, what did you base the sizes on?

I tend to go 1.5-1.6D for the AF

(https://img.photobucket.com/albums/v156/jasonballamy/Hit%20n%20Miss/5-16th%20RnV%20Vertical/DSC01801_zpskgtlhwof.jpg)
Title: Re: 1802 Bell Crank Engine
Post by: sco on February 28, 2019, 12:33:45 PM
Lap engine in the Science museum might be a good reference for what the fasteners should look like:

http://collection.sciencemuseum.org.uk/objects/co50948/rotative-steam-engine-by-boulton-and-watt-1788-beam-engines (http://collection.sciencemuseum.org.uk/objects/co50948/rotative-steam-engine-by-boulton-and-watt-1788-beam-engines)

Simon.
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 28, 2019, 01:01:40 PM
They do look a bit big, what did you base the sizes on?

 :headscratch: I thought I mentioned in my previous post they are the sizes Anthony quoted on his drawings.


Thanks Simon, the science museum also has a bell crank engine which has a mixture of hex and square fixings which is what I am now doing  :)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on February 28, 2019, 01:22:50 PM
Just looked at the article and they are around 2D, hope you did not make all 80 of the small ones before finding they were too big :'(
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 28, 2019, 01:50:45 PM
Just looked at the article and they are around 2D, hope you did not make all 80 of the small ones before finding they were too big :'(

 :(
Title: Re: 1802 Bell Crank Engine
Post by: Jo on February 28, 2019, 04:37:30 PM
This is a fiddly one to put together  :paranoia:

And I am surprised on just how much movement there is on the bell crank  :o

Jo
Title: Re: 1802 Bell Crank Engine
Post by: crueby on February 28, 2019, 05:16:37 PM
Thats a regular pole vaulter!
Title: Re: 1802 Bell Crank Engine
Post by: Johnmcc69 on February 28, 2019, 10:15:43 PM
That's a really nice engine & you have done some outstanding work Jo!
 Where can I find plans of it?  I'm not looking to purchase any castings, I would just like to study the drawings.
My apologies if I have missed that info in another post.

 John
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 01, 2019, 07:44:03 AM
Hi John, thanks for looking in   :).

This design was published in the UK magazine Engineering in Miniature starting mid 1993 (Volume 15) (Polly Model can supply the castings)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on March 01, 2019, 09:04:48 AM
It's also in Antony's book "Historic Engines Worth Modelling" vol 1 which covers several engines and the text is basically the same as the magazine articles. I have seen a video of a scratch built one that just used the book. It's probably cheaper than buying old issues of EiM plus you get another 5 engines as a bonus.
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 01, 2019, 11:47:44 AM
So fiddly  :ShakeHead:

The mounting studs for the pump just would not work - I couldn't get the nuts on  :disappointed: I ended up opting for countersunk screws which I could screw in and the nut would be turned on as they went in and the final little bit tightened with a spanner. The nuts around the cistern were not much easier and I ended up having to use a guide rod to get them to start. I am not taking this apart again  :hellno:

Time to go and have a look at the cylinder assy and see how many fasteners that needs  :toilet_claw:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on March 01, 2019, 12:15:31 PM
Coming together.

Did you use any etch primer under the paint a sit already seems to be coming off in several places?
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 01, 2019, 02:02:57 PM
Did you use any etch primer under the paint a sit already seems to be coming off in several places?

I can't see any primer under the black paint either  :headscratch:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 03, 2019, 02:45:59 PM
The cylinder is now studded up so a quick round and round and up and down test:

https://www.youtube.com/watch?v=2epWetytoz0

The ends of the cotters are rubbing on the stone work and  :facepalm: forgot to do the exhaust pipe: another nasty fiddly bit  :ShakeHead:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Admiral_dk on March 03, 2019, 09:41:37 PM
It looks like it can't be long before it will run on it's own power  :ThumbsUp: good looking too and with an interesting motion  :cheers:

You will get the last bits done too Jo.
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 04, 2019, 08:04:17 AM
Thanks Per  :)

I did get the exhaust pipe done yesterday and etch primed the bits, I should get them painted shortly then there is the faff of trying to get the engine together   :facepalm:


I still need another two bits (why do you keep finding bits not on the drawings  :headscratch: ) I need a steam inlet pipe and a blanking plate for the optional air intake. Then I can start new casting set negotiation again  :cartwheel:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 07, 2019, 04:36:45 PM
Slowly, slowly it comes together :ShakeHead:

At least I have a set of castings to fondle  :mischief:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: b.lindsey on March 07, 2019, 06:42:34 PM
Looks great Jo!!  New castings as well?? Do tell.

Bill
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 07, 2019, 07:06:26 PM
I did post them over on the Triple Orphan thread but clearly the members thought the same as Surus when he saw them that they could not be a real casting set  :disappointed:


We have been fondling them this evening and I believe that Surus is beginning to think that there may be more to them than he first thought  ::)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: crueby on March 07, 2019, 08:14:41 PM
 :lolb:
Title: Re: 1802 Bell Crank Engine
Post by: scc on March 09, 2019, 10:27:30 AM
Hi Jo,    I've just been through this thread again :wine1: ( I dream about making one one day)   I was delighted to see the way you made your cotters and wedges.  I have just sawn / filed in the past, but now the mill is "healthy" I might try your system. (Jan2015)
Thanks for the inspiration.   This forum is great.
Terry
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 10, 2019, 04:10:22 PM
Glad you found it useful  :)

The last couple of bits have been made and attached to the engine. I just need to sort out the valve activation arm and put the cylinder back on the cistern then I could try it on some air  :noidea:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 12, 2019, 01:06:05 PM
What a parliva   :ShakeHead: The arms for the valves are awkward to fit and I had to file out yet more out of the bird beak to get it to turn over without rubbing.

I reviewed Anthony's instructions to find his description of how to set the timing which suggests that the crankshaft should be a movable fit on the end of the flywheel shaft - Yes the engine can move it  :Doh: Then he suggests leaving the top cover off the steam chest so you can see the port opening and closing  :headscratch: I opted for the work out the mid position of the valve and mark the flywheel with a bit of post-it, rotate the engine and mark the same position on the other side.

At this point it was obvious that these two marks were not 180 degrees out so a bit of position fiddling was required to even things out.

After an initial run:

https://www.youtube.com/watch?v=OM_mIJIZYl0

The flywheel moved on the crank  :facepalm: So I now need to work out how to disassemble it, re-time it and do some shaft/arm pinning then I think this engine needs a dark corner with some friendly spiders in which to store it

Jo

 

Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on March 12, 2019, 01:13:22 PM
Coming on, any reason for running it with the bearing caps off?

Think it needs an outing at the weekend before being put away
Title: Re: 1802 Bell Crank Engine
Post by: Bluechip on March 12, 2019, 08:27:34 PM
I'm rather impressed ...  :ThumbsUp:

Some what more animated than the usual err .... 'things'  :headscratch:

Very nice indeed.  :ThumbsUp:

I want two ..  ;D

Dave  ( Off to kip and bemoan snotty conk ...  :'(   )
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 13, 2019, 07:41:10 AM
Thanks Dave it is a very odd engine to watch running. Look after yourself and get rid of that cold/Flu.

Maybe now I will be allowed another set of Castings  :thinking:

Jo
Title: Re: 1802 Bell Crank Engine
Post by: Jasonb on March 13, 2019, 08:07:23 AM
What about that Blued steel, did you get that when you picked up the BR2 castings so the No1 can be finished and then there is that Wall in the background :LittleDevil:
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 13, 2019, 10:38:50 AM
Its just like being married  :ShakeHead:
Title: Re: 1802 Bell Crank Engine
Post by: Roger B on March 13, 2019, 10:52:20 AM
Finally there  :)  :) It's certainly an interesting motion  :ThumbsUp:  :ThumbsUp: I was also going to ask about the wall  :stir:  :wine1:
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 13, 2019, 12:02:11 PM
I was also going to ask about the wall  :stir:  :wine1:

Mine are painted it makes the workshop brighter :)

Jo
Title: Re: 1802 Bell Crank Engine
Post by: MJM460 on March 14, 2019, 11:11:01 AM
Hi Jo, a fascinating action that makes this engine quite different from the standard crank and con rod.

Far to good for the spiders.  Even though the distance prevents me from coming to see it, I do hope you will have it on display at the shows you attend.

Reading back to the beginning, I can see the difficult construction with the cylinder in particular.  I really admire your persistence and ability to get it historically accurate.  I think I would have elected a simplified construction and just kept true to the external appearance.

It would be interesting to see how it would run on steam, in particular how the condenser and water/air pump works in this size.

MJM460
Title: Re: 1802 Bell Crank Engine
Post by: Craig DeShong on March 17, 2019, 06:22:44 PM
FAR too impressive to just become a spider habitat.  Looks very interesting to me.
Title: Re: 1802 Bell Crank Engine
Post by: Jo on March 17, 2019, 06:44:07 PM
Thanks Guys.

I took it to a model engineering meeting yesterday and it got a lot of interest  :)

I have handed it over to Surus to find somewhere to keep it but I didn't get a set of engine castings in exchange :(

Jo
Title: Re: 1802 Bell Crank Engine
Post by: AVTUR on July 30, 2019, 08:12:27 PM
Jo

Did you try running it as an atmospheric engine?

As you know I am building the same model and have just drawn out the valve timing and areas. I have convinced myself that it will happily run on compressed air but not low pressure steam. In essence the valve does not allow the cylinder to fill with steam.

AVTUR
Title: Re: 1802 Bell Crank Engine
Post by: Jo on July 30, 2019, 09:08:16 PM
I don't have a suitable boiler to try running it on steam.

Jo
Title: Re: 1802 Bell Crank Engine
Post by: AVTUR on July 31, 2019, 07:13:34 PM
Jo

Thanks.

I revisited and expanded my analysis this morning and it makes sense. I even got the same setting angle, within 2 degrees, between the cam and crank that Anthony Mount used.

I would like to try my model, when finished, on steam. Therefore I have added a water injector to the condenser.

AVTUR
SimplePortal 2.3.5 © 2008-2012, SimplePortal