Model Engine Maker
Engines => From Kits/Castings => Topic started by: Gas_mantle on April 17, 2018, 04:08:49 PM
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Hi all
With my last project pretty much completed I thought I'd lay the groundwork for my next build. My intention is to try and build hybrid replicas of the Stuart no4 and 10v engines. As far as possible I'd like them to look like the real thing using a mix of castings and barstock.
The idea of this thread came about largely by accident, last year a forum member gave me a 10v trunk guide casting and another member then added a flywheel and a few bits of barstock meaning I had pretty much everything I needed to build the engine.
A couple of weeks ago I was at my local engineering clubs auction night where it's often possible to pick up a piece of junk high quality tooling or barstock at a give away price. As it turned out I came away with a matching trunk guide for a Stuart no4 this time, it is actually a fabricated one but looks well made and only cost £1.40 :)
Fast forward a week or 2 and I managed to buy a no4 cylinder / valve chest casting set at a good price - with a flywheel casting I already have, I now have most of the materials for the no4 also.
The raw materials so far look a bit mismatched but with a bit of imagination I think it is possible to see 2 engines lurking in there somewhere.
(https://i.imgur.com/aKoVySRl.jpg)
I've never built from castings before (other than a small Crosskill engine I tried that was a disaster) so this is something new to me. If other members want to follow along and offer their advice etc I'd be very grateful.
Anyway enough of the preamble, I'll start posting more once the swarf starts curling.
Cheers
Peter.
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Well, I've made a start on the 10v. I wasn't really sure where to begin but settled on the soleplate.
This part is made from cast iron barstock, it isn't a complicated part but does involve quite a few operations and needs to be reasonably accurate to accommodate the bearings nicely and look right cosmetically.
I'm building metric versions of these engines and do have an all metric drawing of this part but I'm not sure how to upload it so here is a photo taken from a book showing what I'm trying to achieve.
(https://i.imgur.com/JM1dLwNl.jpg)
Firstly the cast iron block is squared of and milled to the overall size. I'm not sure what grade of cast iron this is but it machines nicely :)
(https://i.imgur.com/jrebjeJl.jpg)
I've chosen to drill the holes first, then mill the top surface followed by the large centre hole and finally a gentle taper around the outer faces to give a cast appearance. I'm not sure if this is the best way but it seems to me to be the easiest. I'll drill and mill using the handwheels on my mill (I don't have DRO) but marked out the centres that the holes will fall on, these will just form a rough guide that should alert me if I miscount the handwheels etc.
(https://i.imgur.com/gD1A6mrl.jpg)
I bought one of these edge finders for a few quid and it seems to be an improvement on the wiggler set I was using :)
(https://i.imgur.com/ljRN4Z1l.jpg)
Things look to be in the correct place
(https://i.imgur.com/SeCIGCLl.jpg?1)
An 8mm deep 10mm wide slot is milled to take the bearings later. I did consider making rounded bottoms to the slot but chose to keep it simple, so flat it is.
(https://i.imgur.com/droBRXvl.jpg)
That takes me to this.
(https://i.imgur.com/hQbVpJDl.jpg)
With a bit of luck I'll get the rest of it finished tomorrow :-)
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Off to a good start!
:popcorn: :popcorn: :popcorn:
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Slots and holes all accurately placed is always something to be happy about :ThumbsUp: :ThumbsUp:. The more you use the edge finder, the more you will like it. Just don’t forget the half diameter offset :facepalm: Ask me how I know :lolb:
Cletus
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Thanks guys,
I'm not a fan of those ball type wigglers so I bought the parallel sided one, it's a far better and has a point on the other end for centering holes etc.
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Off to a good start with getting all the critical bits done on the first sitting, the rest is really just cosmetic to get it to look like a "casting"
Attached base drawing and another pdf showing it with the barstock bearings and caps
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Off to a good start Peter. Should be a nice build :)
Bill
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the ball wiggler is for flat sides the strait cylinder is for setting to curved sides such as round bar. the farster you can spin it the more responsive it will be.
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The cylindrical edge finder works equally well on both flat edges as well as round bar. Its all I have ever used and don't even own a "wiggler"
Bill
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The reason I bought the cylindrical edge finder was mainly just for the convenience of it being metric, the ball wiggler I have is 1/4" dia and I just found it a bit of a chore having to allow 3.17mm radius into the setting up. The cylinder is 4mm dia so it is less prone to error adding 2mm than 3.17mm.
As it happens I do now prefer the cylinder version but the wiggler works well when using the point to locate a centre mark when using the 4 jaw in the lathe. (Admittedly its a 3 jaw in the photo but you get the idea :) )
(https://i.imgur.com/AgPUFDBl.jpg)
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I'd hoped to get the soleplate for the 10v finished today but things didn't quite go to plan although I did make some progress.
Originally I had planned to mill the steps in the top surface but after a rethink I decided on milling out the centre next. Unfortunately my 4mm slot drill proved too short to go right through. It can be seen here that the wider non cutting part of the mill is starting to foul, I'm not concerned about the fouling mark as that is later to be milled down but the cutter isn't going to go through :(
(https://i.imgur.com/YXYUEGvl.jpg)
I decided then on using a 4mm drill to drill through on the 4 corners.
(https://i.imgur.com/4uW6o8cl.jpg)
Somehow I had it in mind that the drill would get round the problem but really I'm no further forward, I need to use a cutter no larger than 4mm dia in order to preserve the radiussed corners but every other cutter I have still can't cut the depth I need.
So it's back to the 4mm milling cutter
(https://i.imgur.com/q4O5mRul.jpg)
The idea now is to go as deep as I can then flip the part over to cut the remainder. It's not Ideal but I have a vice stop in place and I'm working from the dials so I'm hoping I can just about get the cuts to meet up.
(https://i.imgur.com/wovy1q9l.jpg)
Well that's reassuring, with the part hard against the stop the first hole lines up perfectly :)
(https://i.imgur.com/1qunFx1l.jpg)
Join the dots
(https://i.imgur.com/zrcy9wkl.jpg)
It's a little bit out but a bit of emery or the Dremmel will correct the small mismatch.
(https://i.imgur.com/VDAVqh9l.jpg)
Peter :)
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Well done. :ThumbsUp:
I wouldn't have had a chance to get it that close.
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Continuing on with the 10v soleplate the next task is to machine away the 4 corners to a depth of 5.5mm, I'm wanting to try an create a cast appearance so I thought I try and create rounded internal corners. I don't have a ball end mill long enough to reach (I've settled on 2mm dia) so I gave it a try drilling from the sides with a 2mm drill.
(https://i.imgur.com/goYRjDdl.jpg)
Then start milling away the waste.
(https://i.imgur.com/evGcz4Wl.jpg)
Some corners are better than others :(
(https://i.imgur.com/KjARGtCl.jpg)
I think a bit of filing and polishing will lose the error
(https://i.imgur.com/ZlySnr4l.jpg)
The final job is to cut a shallow taper on the 4 sides, I wasn't really sure of the best way but thought using the swivel base on my mill vice could be worth a try. I've had it 18mths and it's never been used so today is it's first outing. The graduations are a bit small but I'm not interested in achieving a specific angle, I just want all 4 sides the same and realistic in appearance.
(https://i.imgur.com/0QXkGYnl.jpg)
It's just about visible here that the vice is angled for a test cut on a piece of scrap
(https://i.imgur.com/Xqmfncjl.jpg)
That looks about right
(https://i.imgur.com/zZOUUG7l.jpg)
The hold in the vice isn't great but the cuts are small
(https://i.imgur.com/WEV3YFCl.jpg)
(https://i.imgur.com/v7g3H2Pl.jpg)
My largest milling cutter has just about enough depth
(https://i.imgur.com/KxttyGgl.jpg)
A bit of light filing and emery takes me to the finished part.
(https://i.imgur.com/snZfro1l.jpg)
(https://i.imgur.com/MuYNcHIl.jpg)
It has got a few dwell marks and scrapes but I'm happy it has lost the 'Lego block' look and does at least look a bit like a casting :)
Peter.
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Looks great!
:popcorn: :popcorn: :popcorn:
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Took me a while to figure out what you did.
You basically used your swivel base as a rotary table, no? Pretty neat.
I hadn't seen that before.
:ThumbsUp:
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Cheers guys.
Carl, I used the swivel base to position the vice so it is no longer parallel with the table then made fine cuts across the end of the work piece. The vice wasn't moved once I had positioned it 1 or 2o off parallel.
It seemed to work ok but I think I should have cut a slightly more angled taper.
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I had intended making the crank bearing next but haven't yet decided the best way so I opted for doing the crankshaft first. I decided for a small engine a fabricated one will be fine but may turn one from solid for the no4 engine.
2 steel blocks drilled to take the shafts will form the webs
(https://farm1.staticflickr.com/967/26802596537_c8269e4159_c.jpg) (https://flic.kr/p/GQsjap)
A 7mm rod will form the crank pin
(https://farm1.staticflickr.com/906/27801592128_a55692e92a_c.jpg) (https://flic.kr/p/JmJqKj)
I did try the rotary table to cut rounded end for the webs but it was far from ideal
(https://farm1.staticflickr.com/866/27801623198_abcefaffdc_c.jpg) (https://flic.kr/p/JmJzZ1)
So it was over to the lathe, this looks a bit primitive but worked well for a few small cuts
(https://farm1.staticflickr.com/970/40779928575_d381846c88_c.jpg) (https://flic.kr/p/258zN1P)
They turned out ok :)
(https://farm1.staticflickr.com/912/27801685568_16b930b226_c.jpg) (https://flic.kr/p/JmJUwm)
So bit of 638 (or the green stuff as Zee calls it) and they were left overnight. I may pin the webs later but it's probably not needed on a tiddler engine like this.
(https://farm1.staticflickr.com/901/26802940467_cfbaa129a3_c.jpg) (https://flic.kr/p/GQu5pe)
Milling out the waste
(https://farm1.staticflickr.com/957/26802917247_0929a014cc_c.jpg) (https://flic.kr/p/GQtXuT)
That takes me to this
(https://farm1.staticflickr.com/945/40960188144_cf518f1be2_c.jpg) (https://flic.kr/p/25pvEUq)
(https://farm1.staticflickr.com/835/27801639958_b5059a2bb3_c.jpg) (https://flic.kr/p/JmJEXY)
Peter.
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For your bearings I would mill the two blocks to overall size. Then mount in the vice and indicate from top and one side to find the middle and then drill and ream the hole. Now rest on packing and set up in the vice holding by the two faces and indicate off the fixed jaw to find middle of the bearing and mill a slot, rotate to do all 4 sides keeping the same face against the fixed jaw. Finally mount on arbor to turn the faces round with a round nosed tool. There are a couple of pics of how I did the 24 vertical in that set.
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Cheers Jason, the bit I'm undecided on with the bearings is how to hold the small blocks in the lathe accurately enough so that I can turn the small raised rings at either end concentric to the bore, then turn them round and repeat etc.
I was going to turn each end in the 4 jaw and spent time setting up 4 times but it kinds seems to me there must be an easier way ;-)
Can you post an image of the bearing or plan ?
Thanks :-)
Edit - sorry, I see what you mean about an arbor now.
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have a look at the big end bearings being done.
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Thanks, it's kinda obvious now you have mentioned it :)
I'll cut the squares later and turn them tomorrow.
I have a collet system and some collet blocks on my shopping list for Doncaster in a couple of weeks to help with this sort of thing. (I think a faceplate could be useful for the no4 trunk guide too)
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Today I decided to tackle the main bearing blocks, they are made from pieces of 24 carat gold machined to 12mm square and 15 mm long, a central hole is then drilled for the 7mm shaft.
(https://farm1.staticflickr.com/827/40820287815_7faa45082c_c.jpg) (https://flic.kr/p/25c9DpM)
A thinner waist is then cut, this will fit in the upright pillars of the soleplate. I don't have an end mill the width of the cut I need but by cutting it in this orientation the stop buttons on the front of my mill table can be set to limit the x axis travel to ensure repeatability.
All 4 faces are cut with the part firmly against the vice stop.
(https://farm1.staticflickr.com/906/26851787027_1a26ce6ddd_c.jpg) (https://flic.kr/p/GUNqMi)
So far, so good...
(https://farm1.staticflickr.com/979/39912308460_a4b375dce3_c.jpg) (https://flic.kr/p/23NV1Mj)
To cut rounded rings at each end I made a temporary tool from a broken parting blade, a test cut on a piece of scrap is made to test the profile.
(https://farm1.staticflickr.com/903/39912294240_edb592c76b_c.jpg) (https://flic.kr/p/23NUWy9)
The blocks are then turned on a close fitting mandrel.
(https://farm1.staticflickr.com/863/41001966574_1a90ab582b_c.jpg) (https://flic.kr/p/25tcNbb)
That takes me to this stage
(https://farm1.staticflickr.com/946/41719405981_68141f4d08_c.jpg) (https://flic.kr/p/26yARV8)
(https://farm1.staticflickr.com/972/41679174332_161dd96d19_c.jpg) (https://flic.kr/p/26v3Es1)
Overall I'm happy with how they turned out, the shaft lies squarely and rotates freely without any play :)
(https://farm1.staticflickr.com/956/26851811377_58712670f9_c.jpg) (https://flic.kr/p/GUNy28)
(https://farm1.staticflickr.com/912/40820342235_f88c38a0ca_c.jpg) (https://flic.kr/p/25c9VA4)
Brass plates will next be machined to hold the bearings in position
Peter.
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:popcorn:
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They look great.
Neat trick using the parting tool.
But I can't quite figure out how you did it. Did cut at an angle through the steel cylinder?
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The steel cylinder is just a piece of scrap used as a thick spacer / washer, all I did was to angle the tool post like it is for the scrap brass in the previous photo then gently plunge in using the handwheels to measure the cut and get them both the same
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Rather than clutter up Graham's thread I just had a look at the costings for a No4 cylinder etc
Stuarts want £82.44 for the cylinder, valve chest and valve chest cover castings.
You could cut all three from a 3" long piece of 70x70mm square cast iron which would set you back £25.20 using M-machine prices.
Not sure where you worked out that it would be cheaper to buy the castings :headscratch:
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I bought the castings from another forum member at a reduced price so I didn't pay £82, once I factored in the postage on the barstock there wasn't a great lot of difference.
I'd like to have made from stock but when I can have a casting set for a similar price it seemed to make sense.
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I was forgetting you used an alternative supplier.
May explain why Jo thinks casting sets are good value for money :LittleDevil:
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To someone like me who has limited experience a casting of that size will probably look better than a barstock one, I already have the trunk guide so in the interest of making the whole engine look attractive I bit the bullet and bought the castings since the price was similar.
The rest of the engine I think I can make from stock and it should look ok, it goes against the grain a bit with me in buying castings but in this case it just made sense :)
The £80 I mentioned to make the engine in another thread was for everything needed to make the complete engine :-)
I want the no4 to be a fairly powerful engine - any thoughts on pistons / rings ? The graphite yarn I use on small engines doesn't sound ideal so I have considered trying to make from cast iron.
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You hardly see any of the cylinder once the cleading is in place ;)
Why not have a go at making a couple of CI rings, piston could be either iron or aluminium
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I'm happy to have a go at making CI rings, if it's not a success I haven't lost much.
What are Stuart pistons made of on this engine? I had looked at CI pistons but from what I read like materials are a no no
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The Stuart piston is cast iron.
CI is one of the materials you can run on itself and lets face it the piston does not really touch the sides it's the iron rings that run on the iron cylinder walls
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Thanks, I'll try CI and see how we go, with small easy to make components I'm happy to try a few different materials and see how we go.
I have a piece of stock ready to make the no4 soleplate next, I'd like to make the 2 engines stage by stage together if I can. Really I could do with a faceplate for turning the trunk guides so for now I'll leave them until after the Doncaster show and buy one there.
My intention is to try and machine the no4 crankshaft from solid, I've never tried doing it before so if anyone has any tips/hints I'd be grateful :)
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I guess a 2x scale doesn't sound a lot till you equate that it is 8x the volume and weight :o
(https://farm1.staticflickr.com/959/41757978321_1d0de2bb0a_k.jpg)
(https://flic.kr/p/26C1y8t)
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My intention is to try and machine the no4 crankshaft from solid, I've never tried doing it before so if anyone has any tips/hints I'd be grateful :)
Well as nobody else has offered any help here goes.
At the size of the No4 it's a toss up whether to use round or flat stock, round would allow you to do integral balance weights which are not shown on the drawings but may be handy if you want to run it fast for generating. If you don't want weights then you can machine the whole round down to a flat with rounded sides first or just mill the two round webs flats at the end. If starting with flat then black (hot rolled) will be less likely to move, if you go for bright then stitch drill out and leave for a couple of weeks to settle.
Rather than go through the process have a look back at a couple of cranks from my build threads and then come back with any questions.
http://www.modelenginemaker.com/index.php/topic,6471.msg134411.html#msg134411
http://www.modelenginemaker.com/index.php/topic,3397.msg63805.html#msg63805
I always like to get the crank done early on and then use that as a plug gauge when boring the bearings, flywheel, eccentrics, pulley, etc If you do get any chatter or deflection and have to go a bit undersize then you won't end up with all the other parts wobbling about
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Cheers Jason,
I was kinda thinking to keep things relatively simple I'd make from flat bar. I was looking a 12mm dia so I thought a piece of 5/8ths thick steel should do. Making from round hadn't occurred to me, I guess the idea of weighted webs is attractive as I'd like the engine to run reasonably fast without the shakes ;)
At the mo I've started to make the no4 soleplate but tomorrow I will see what sizes of flat and round steel I have then have a think about it. For the no4 box bed I think I'll fabcricate from 4 pieces, trying to make from solid in that sizes seems wasteful and time consuming.
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If you can weld you could make up the box bed quite easily, similar to the one I did for the lightweight. If not Aluminium and screw/JBWeld construction.
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I cant weld so I'm thinking of bolting the sides together with capheads below the surface. I thought if I plug the holes with JB weld then blend a curve on the corners with a file and emery it ought should be ok under paint.
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for the crank shaft when i built the no4 i had the original stuart turner supplied material .i have made several seats since i have used m200 for several a heat treated machinery steel.a rectangular piece machined straight and square to the size of the webs.Held in the four jaw chuck set up to marked out centre of the journals then centered and supported by a live centre set up with a dial indicater to be parallel to the centre line of the lathe.
i have left the end with the centre untill the rest has been done. big end finished then final finished the mains between centres. stuart no .1 size.I turned one at work ,i was asked if i could do it on a friday afternoon.
the old one had worn the big end right away just the two pieces.I just said can you get a piece of material,
it was 8 inches did about 18 inches long ,3 inch journals for 3 inch of set for 6inch strock apiece of m200 was waiting on monday morning.when finished it was hardened by nitriding.i did this the same way using left and right handed tools .
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That method of doing the boxbed will be fine, much like I did the recent Vertical.
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:-X
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Re. balance weights on the webs, I made up steel flyweights machined from flat section BMS for my Stuart No 1, with the slot a nice close fit for the crank webs, secured by a 2BA cap screw and plugged over the screw head. Dave
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Thanks Jo it's a shame Stuarts don't make their castings a bit easier to machine for thos ethat have them, if they were cast like this it would be so much easier for the beginner.
(http://img.photobucket.com/albums/v156/jasonballamy/Hit%20n%20Miss/Half%20Scale%20Gade/IMAG3580_zps99pimfve.jpg)
EDIT. I should correct that statement, Stuarts have seen the light :praise2: and don't supply cast cranks For the No4, 10 or most of the other engines anymore. :LittleDevil:
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Thanks all.
John, do you have a photo or a build log of your no4 as I'd like to see it :-)
Dave, it's funny you mentioned adding balance weights as my Stuart 10h has what seems to be similar albeit a bit simpler. (I didn't build it)
(https://farm1.staticflickr.com/951/26958013417_c68d6cce16_c.jpg) (https://flic.kr/p/H5bSbM)
(https://farm1.staticflickr.com/977/41109330544_3cddb269a5_c.jpg) (https://flic.kr/p/25CG4K7)
These engines are very much make it up as I go along projects so I'll make the crank and decide what to do about weights later. It's likely to be the weekend before I start on the crank.
I have also bought a 10v casting kit on ebay, it should arrive tomorrow, I'm not sure how old it is so I'll be interested to see what sort of crank comes with it.
It will be my first fully made casting engine - I do hope I don't turn into a closet casting fondler :stir:
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It will be my first fully made casting engine - I do hope I don't turn into a closet casting fondler :stir:
You've already opened the door. You may as well go in. Or is it out?
No matter. ;D
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It will be my first fully made casting engine - I do hope I don't turn into a closet casting fondler :stir:
It is perfectly safe so long as you continue to admit your addiction ;) Think of fondling sets of castings as a motivator keep your energy focused and encouraging you to get out in your workshop rather than sitting there growing old until you are not strong enough.
As a fellow model engineer (96 years young) once said to me: I know I am going to live at least a couple more years as once I finish this model I still have to build that locomotive that I have the castings for sitting on the shelf but it will probably only take 18 months so I might need another set for the engine after that 8) Sadly he forgot to buy the extra set but he did finish building and ran the Loco that he already had those castings for :ThumbsUp:.
Jo
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I blame you for the slow onset of casting fondling syndrome - I was fine till you gave me the 10v trunk guide, a few weeks later you referred me to a casting supplier and I came away with a no4 cylinder casting. Now to make matters worse I have bought a full set to make a 10v ;)
Before long I will be at Casting Fondlers Anonymous, sitting in a circle holding hands - "Hi, my name is Peter and I'm a casting fondler".
:)
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A piece of barstock twice a day will soon have you cured before it's too late :Lol:
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This little project seems to be getting bigger everyday. It started as a hybrid 10v, then a hybrid no4 came along, today a full casting set for a 10v has appeared :-
(https://farm1.staticflickr.com/950/26998594067_6b6acbdaee_z.jpg) (https://flic.kr/p/H8LRpa)
It looks to be a new style one as it has a fabricated crankshaft.
I have this awful feeling I'm turning into a casting turning cissy :stir:
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Hee hee hee.
I haven't seen too many people get this hooked this fast before.
You need help...
don't seek it. ;D
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I haven't seen too many people get this hooked this fast before.
You need help...
I gave him my casting supplier's telephone number ::)
Jo
P.S. I hear my supplier has more interesting sets available :-X
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P.S. I hear my supplier has more interesting sets available :-X
Yes Jo but you gobble them all up and leave nothing for the rest of us, it's no wonder Jason is skilled in barstock building ;)
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Yes Jo but gobble them all up and leave nothing for the rest of us, it's no wonder Jason is skilled in barstock building ;)
Not yet she hasn't :hellno: And there are a few rather nice ones available that she has already made one of her own ;)
Don't believe JBWeld he has made as more engines out of castings than bar stock... It is just he tries to deny his addiction :disappointed: It is only when you admit to an addiction that you can move forward and find a solution. Like recognising the need to retire so that you can make all the engines you have castings for :pinkelephant:
Jo
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Steady now Jo you are giving me Ramon's nickname. Also the last time I counted up which was about 10 seconds ago it was about 40/60 with the larger proportion being without castings.
Have a look through this lot (http://www.model-engineer.co.uk/albums/member_album.asp?a=40619) and see for yourself, the 10V is not there so add that to the castings list.
j
BTW they are almost all painted, complete and run ;)
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The Cameron steam pump looks an interesting piece, is there a build log to look at ?
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And lets discount the ones where you chose to build from the commercial drawings that went with a casting set (often doubling up to try to hide the fact)... Someone would think you were trying to collect moths :lolb:
BTW they are almost all painted, complete and run ;)
We haven't seen the Robinson Chippy engine or the Otto Langen running either.
Jo
P.S. The Cameron Pump was another scaled up from the original drawings from the casting set :ShakeHead:
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The Cameron steam pump looks an interesting piece, is there a build log to look at ?
Yes it was far more interesting for me to make it from scratch rather than unavailable castings, build below with not just JBWeld but also proper welding, silver soldering or just plain old hacking it from solid
http://www.modelenginemaker.com/index.php/topic,4438.0.html
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Thanks, would it be able to pump at a reasonably high pressure to fill a boiler ?
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Don't waste your time Peter if you want a nice practical pump for your boiler build one of Bob Potter's Southworth pumps: http://www.southworthengines.com/steam-feed-pumps/vertical-steam-pumps/
Eric keeps offering me the set of original Camoron pump castings at ever reducing cost as no one wants them :facepalm: there are much nicer engines to spend your limited time making :)
Jo
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It's really no different to a lot of other feed pumps, just looks a lot nicer than most. Had I intended to use it on steam for a feed pump I would have silver soldered a bit more of the main "casting" rather than JBWelded it, the rest is upto the task.
It's quite a large cylinder so will need a lot of steam
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just looks a lot nicer than most.
That is your opinion. ::)
Jo
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Don't waste your time Peter if you want a nice practical pump for your boiler build one of Bob Potter's Southworth pumps: http://www.southworthengines.com/steam-feed-pumps/vertical-steam-pumps/
Jo
I'm looking at getting a new boiler later in the year so I guess I was just thinking aloud in asking about pumps, I will at some point be interested in a feed pump but that's quite a way forward yet :-)
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You may be better off with a small feed pump on the No4, don't think Stuarts do one but the one for the No9 could probably be adapted or easy enough to make one with a few bits of brass and some silver solder, could even just make the body from a solid block if you don't feel upto soldering.
Worth thinking about when making the sole plate as you can leave some flat area to fix the pump to.
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Hmmm, adding a pump to the no4 is worth thinking about :)
A lot will depend on the boiler I get, at the moment my eyes keep looking toward the Castle instrments V6
http://www.castleinstruments.co.uk/Products.html
I seem to remember reading somewhere that the boiler can actually drive a twin 5a albeit probably not under any great load.
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Peter if you intend on only using a boiler for one specific engine then it is worth running a boiler pump with that engine. If not then a stand alone small duplex which includes the steam cylinder might be worth thinking about. Of course there is also the option of a steam injector.
A 6" diameter boiler is a big beast as big as a standard gauge 5" Locomotive boiler goes - it would easily turn over a Stuart Swan.
Jo
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Yes inclined to agree with Jo that it may be better to make a complete steam plant with hand and steam pumps, water tank etc then you only need to hook up the inlet and exhaust for whatever engine you intend to run. If so then practicality would over ride appearance.
Also thinking about the No4 boxbed, if you are going to run a generator/dynamo then it may be an idea to have an extended bed and mount the unit to that and to save issues with belts put it inline with the crankshaft which is how a lot of gensets are done.
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A 6" diameter boiler is a big beast as big as a standard gauge 5" Locomotive boiler goes - it would easily turn over a Stuart Swan.
Jo
Is a Stuart swan a twin 5a? I get confused as there isn't one in the current range. Was it actually an engine in its own right or a nickname for 2 separate 5a's permanently coupled ?
Thinking about the boiler like I say I'm very much still at the stage of mulling over the options, I definitely need a replacement for the one I have and it makes sense to upgrade at the same time. I might treat myself and the V6, it's a monster boiler but my thinking is I'll never need to upgrade and it will power anything I'm likely to build.
I want a self contained plant to power a variety of engines with it's own in built feedwater supply. A lot will depend on which boiler I buy and how much water it needs after assessing it in use. Using a bit of guesswork I'd expect one of the 10v's to be too small for a V6 boiler but a no4 looks like it might have the guts.
The self contained pumps from Southworth etc are nicely looking items and something in the back of my mind. I'm let to believe they are difficult to build yet they are hideously expensive to buy ready built. (I guess it goes without saying something that isn't easy to make will be costly )
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The Swan is two Cygnets on a common sole plate, both are basically the same mechanically as a 5A but the Cygnet and Swan were available in condensing form which included vacuum pump, feed pump and mechanical lubricator and were ideal to use to power a boat.
The Non condensing Cygnet is more or less a 5A set of castings with the reversing gear included in the one package, the reversing gear for the 5A is an extra.
The Stuart feed pump may be another one to think about, I think that looks nicer than the Southworth ones
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I guess like all other sellers Stuart keep altering the range of engines available.
Co-incidentally while I type I've just had an email from them showing a new addition to the range - a V twin no7 :)
http://www.stuartmodels.com/products/set-of-castings
(https://gallery.mailchimp.com/f769ec8e9648b9e72d7e83c7d/images/6e926eda-5429-4e0c-9f5d-e08697c24bb3.jpg)
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Think they might sell more if they showed a photo of it :-\
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Think I will pass on that one, does not float my boat :(
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The Stuart feed pump may be another one to think about, I think that looks nicer than the Southworth ones
and there are lots of non working stuart feed pumps kicking around as they are not a beginners build and they also cost more that the small Southworth pump.
Jo
P.S. Peter, our casting supplier has about 20 sets of castings for the Stuart steam pumps kicking around :-\
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Cheers Jo, I'll bear that in mind once I have a new boiler and able to properly assess what I need.
I'm not keen on the look of the Stuart 14? either :( I think the D10 is a nice looking twin so I'd of preferred the new engine be a scaled up version of that.
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Bit hard to tell from the photo but it does not look like the base is a casting, so all they have done is come up with a different arrangement of what they already have. The contents looks to have been cut and pasted from the 7A details
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The photo itself is just the one the included in the email to me, I just added it when I realised the website doesn't yet show it.
It looks to me like it would be easy for the trunk guide to be snapped from the base - its hard to see in the small photo but it looks like only 2 studs hold the each assembly to the base ? I'd have thought if you cut a leg off the trunk guide you'd need some extra bracing etc ?
I guess they must know what they are doing and we'll soon see better photos.
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Must...look...away...
Else I will get bitten.
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It's a bit like a No 1 or even the original No7* which have one main standard held by two fixings and a brace, in this case the brace goes between the two standards rather than back down to the soleplate.
* originally the No7 was like the No1 but they put it on an A frame standard and called it the 7A, the original No10 was the same and only became the 10A when put on teh A frame standard.
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It's a bit like a No 1 or even the original No7* which have one main standard held by two fixings and a brace, in this case the brace goes between the two standards rather than back down to the soleplate.
* originally the No7 was like the No1 but they put it on an A frame standard and called it the 7A, the original No10 was the same and only became the 10A when put on teh A frame standard.
It is nothing like a No 1 :hellno: or the 2, 4, 7 or 10 each have a flat parallel guide to the side of the cylinder that new engine has a circular guide akin to cutting off one leg of the modern A frame. The original No 5 had two legs with a flat parallel sided cross head between them not the modern A frame circular guide/crosshead :ShakeHead:
Jo
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By Similar I meant a standard on one side and the turned post on the other, was not refering to trunk or flat guides, both have the standard fixed with two screws and the post so the 7V will be no weaker as the question was about the strength of the standards fixings. :wallbang:
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This is my no. 4.I don't have a build log as this was back when it was still the original start turner
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Thanks John, great looking engine :ThumbsUp:
Do you ever run it on the hot stuff ?
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This was the first stuart turner engine i built it has always run on the real , hot stuff .it doesn't run as fast smoothly like the 5a but still runs well. Piitty it has not got balance weights like the 5a.
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Thanks, I did wonder about adding balance weights to my no4 replica, I intend to try and make the crank from solid and with have a think about it.
Progress has been slow this week but I thought I'd show just a few photos of where I'm up to so far.
I've now partly made the sole plate from a cast iron block. The trunk guide I bought is more irregular than I thought at the feet so I decided to take the back to front step of evening up the guide as best I can then mounting it on the sole plate and machining the plate to fit :headscratch:
(https://farm1.staticflickr.com/945/41274050065_1597dbffff_z.jpg) (https://flic.kr/p/25Tfi7R)
With soleplate channel milled out I've now set about mounting the guide to run true to it, tomorrow I'll try and get the detailing cut on the soleplate now that I can see where the trunk guide sits.
(https://farm1.staticflickr.com/831/42174685171_a86594e422_z.jpg) (https://flic.kr/p/27fQhyk)
(https://farm1.staticflickr.com/962/27303013767_c9a68b0054_z.jpg) (https://flic.kr/p/HAF5LF)
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looks like your making good progress.
The first engine i made was similar to a no 10 v that i turned from round bar so had full disk crank webs ,that also runs smoothly.
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Thanks John, I'll have a think about how best to tackle the crankshaft over the next few days. I'd like this engine to be reasonably powerful (possibly to drive a dynamo or a decent sized boiler feed pump) so I'd prefer a solid crank if possible.
I'm pleased to say the soleplate is now largely complete :) I wanted radiussed corners where the raised parts rise up so I decided first to cut channels using a 4mm ball nose mill.
(https://farm1.staticflickr.com/971/27321121317_2c4904feb2_z.jpg) (https://flic.kr/p/HCgTvP)
Then mill away the 4 corners
(https://farm1.staticflickr.com/907/42146036912_69a8e99b2a_z.jpg) (https://flic.kr/p/27disqQ)
A 10mm dia end mill had just enough depth to cut out the centre and give a suitable radius in the corners
(https://farm1.staticflickr.com/944/42192365721_14495eb42f_z.jpg) (https://flic.kr/p/27hoUnp)
That takes me to this point, a little bit of emery should tidy things up a bit so I'm quite pleased so far.
(https://farm1.staticflickr.com/975/42192419411_c99e74dfc8_z.jpg) (https://flic.kr/p/27hpbk6)
(https://farm1.staticflickr.com/956/40385516000_380b4f1554_z.jpg) (https://flic.kr/p/24wJjU1)
(https://farm1.staticflickr.com/953/41291982965_817b73a0f9_z.jpg) (https://flic.kr/p/25UQcWM)
I'll try and get the side tapers cut tomorrow then that should will complete the soleplate :)
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While the toffs were getting married I thought I'd finish off the soleplate, so it's on to cutting the shallow side tapers.
I only have 1 small angle plate and little in the way of mounting hardware so holding this part proved to be a challenge but eventually I settled on this arrangement of 1 vice held in another, it looks a bit unstable but is more solid than it looks and I only have a small amount to material to remove.
(https://farm1.staticflickr.com/948/27341344887_f6e7c63547_z.jpg) (https://flic.kr/p/HE4xh4)
To cut the end tapers would have too much sticking out of the vice so I chose to mount my mill vice on its rotary base and set it about 5o off parallel.
(https://farm1.staticflickr.com/828/28339732598_8caeccf879_z.jpg) (https://flic.kr/p/Kbhxah)
It seems to have the desired result :)
(https://farm1.staticflickr.com/945/41311917515_bcd1483415_z.jpg) (https://flic.kr/p/25WAnMV)
Final job is just to mill a small amount off either end to the correct length and ensure they are even
(https://farm1.staticflickr.com/912/42212131691_48225eb50c_z.jpg) (https://flic.kr/p/27j9d6Z)
That takes me to the final result
(https://farm1.staticflickr.com/831/41491634124_f7967ac18a_z.jpg) (https://flic.kr/p/26dtth9)
(https://farm1.staticflickr.com/824/28339832268_d9671e4f21_z.jpg) (https://flic.kr/p/Kbi3MJ)
I'm quite happy with the result, there are a few dwell marks but I think they'll polish out and it does at least resemble a casting.
It's not till you see a no4 and a 10v together that you realise how much the size difference is.
(https://farm1.staticflickr.com/906/42212581701_a77267829a_z.jpg) (https://flic.kr/p/27jbvSM)
Next job will be to make the bearings and have a go at cutting the crankshaft from solid.
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Nice work! I like the fabricated upright part...
Pete
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It's not till you see a no4 and a 10v together that you realise how much the size difference is.
and the 4 is rather smaller than the 5A or the Swan :embarassed:
Jo
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and the 4 is rather smaller than the 5A or the Swan :embarassed:
Jo
When you decide to raid your fondling casting cupboard and sell me a set of castings I might have a go at making one :-*
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Although I'd intended making the no4 crankshaft next I had a change of plan and decided to make the cylinder next.
I was lucky enough to buy a casting from another forum member at a reasonable price and this was the first time I've machined a cylinder from a casting so wasn't too sure how it would go. The outer edge of the flange is pretty much the same diameter as the trunk guide to so it seemed to make sense to get that running as true as possible and not worry too much how the bore was.
Some people complain about these budget brazed carbide boring bars and I guess some are better than others but this one usually does a decent job and doesn't suffer a lot of spring back
(https://farm1.staticflickr.com/912/42184645902_600c5b77d7_z.jpg) (https://flic.kr/p/27gHkx5)
Once bored out to the required 1.5" dia a cheap and cheerful cylinder hone in the tailstock gives a good finish
(https://farm1.staticflickr.com/911/42184687542_c755628c9e_z.jpg) (https://flic.kr/p/27gHxV1)
(https://farm1.staticflickr.com/906/42231131781_716967ebcd_z.jpg) (https://flic.kr/p/27kPAaK)
A quick milling job to prepare the port face and the exhaust gland boss.
(https://farm1.staticflickr.com/957/27364743417_0a27a8f724_z.jpg) (https://flic.kr/p/HG8sQZ)
I don't know whether is usual practice with Stuart cylinder castings but this one has the ports and passages leading to the cylinder bore cast in but the exhaust port needs to be cut by the builder. The port needs to be 1/4" wide but I wanted the corners as square as I can make them so I used my smallest slot drill of 3/32"
(https://farm1.staticflickr.com/980/41334431635_b5f5733d9a_z.jpg) (https://flic.kr/p/25YzLsp)
So far so good :)
(https://farm1.staticflickr.com/975/28362299968_7828427d2e_z.jpg) (https://flic.kr/p/KdhcDS)
I don't have a 1/4 drill for the exhaust outlet but 6mm sounds a good substitute.
(https://farm1.staticflickr.com/831/42189062652_4aac5e7dc2_z.jpg) (https://flic.kr/p/27h6YtW)
That takes me to this stage, I'll drill for the end covers and valve chest once I've made them.
(https://farm1.staticflickr.com/981/27364765887_3d8a673503_z.jpg) (https://flic.kr/p/HG8zwp)
There is a small cavity in the casting at the edge but if I remove any more from the face I'll start eating into the gland boss, once I have a gasket fitted I don't expect there to be a problem
(https://farm1.staticflickr.com/978/41334377045_ec4611915b_z.jpg) (https://flic.kr/p/25Yzuec)
All being well I'll get the end covers made tomorrow, the only slight snag I can see is there isn't much material to hold onto when turning the top cover but I'll come up with something.
(https://farm1.staticflickr.com/946/42184657892_875dc7a6cd_z.jpg) (https://flic.kr/p/27gHp6N)
Peter.
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Looks good :)
and the 4 is rather smaller than the 5A or the Swan :embarassed:
Jo
When you decide to raid your fondling casting cupboard and sell me a set of castings I might have a go at making one :-*
I don't have any more 5A's the only other large Stuart Steam engine I have is the No 1 :embarassed:
Yes Stuart do like to cast in only the inlet ports and leave us to machine the exhaust port.
Jo
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Thanks Jo, are you implying you may have a no1 casting kit for sale :)
I'm enjoying the challenge making these 2, I'm unfamiliar with castings so it's a bit of a learning curve. The only slight snag at the moment with the no4 is I think the dimensions may have changed over the years. I have a home made trunk guide, a cylinder casting from a different source and a set of plans that are different still, add to that I'm trying to make it in metric from imperial plans and there is plenty of scope for error.
The plans show the total cylinder length at 2" but mine even after machining is 21/4, if you look at the earlier photo, taking another 1/8 off each end would get very close to the ports so something isn't right.
It isn't a problem but somewhere along the line I think the dimensions have been changed so not all castings are compatible with all plans :headscratch:
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Thanks Jo, are you implying you may have a no1 casting kit for sale :)
:lolb: :hellno:
My drawings show the cylinder at 2 1/8" long
Jo
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I have 2 sets of plans one is like yours but the one I'm working off is different so something has changed along the way.
My guess is the one I'm using is in old money and yours is in the new money.
(https://farm1.staticflickr.com/971/28366369858_d333bc8a4b_z.jpg) (https://flic.kr/p/KdD4uo)
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my no 4 cyl casting finished is 2"long my no9 is 2 1/8 but your working with castings .so you will have to work to the casting adjust the sizes to suit the casting you have.
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The newer 2007 drawing uses a 5/8" thick piston and the older 1953 drawing 1/2" so that is why 2" fits the old engine but a 1/8" longer cylinder is needed for the new one. No doubt the longer piston is needed as Stuarts have moved over to O rings rather than the thinner CI rings
I would not touch the ends now as setting it back up to get the standard end true to the bore will be hard, make your piston 18mm long and the cylinder cover spigots 2mm which will compensate for the extra length created by your 2.25" cylinder
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Just a thought before you get too far in, you said you bought the cylinder set which should have included the valve chest. Check the length of that to make sure it will machine to 2.25" as if it is going to end up shorter that would look odd. New chest should not have the bit at the top for the valve rod as it has changed to a separate part.
Back to the question of ports, it depends on the particular engine, about 2/3rds only have the inlets but the remaining 1/3rd also have the exhaust cast in. Don't forget to poke some wire down the ports to remove any remaining sand.
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The valve rod and piston rod length may need adjusting to siut.
Have they just made the same cylinder casting for the no4 and no 9.?
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Or more likely you have been sold a No9 Cylinder set which is for a 1.5" stroke engine rather than a No4 Cylinder set which is 1.25" stroke. Was it still in its packing?
Possibly they now just use the one casting but I've not seen a new No9 drawing to be sure.
J
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Thanks guys,
It is a no9 casting (the letter s on the chest cover is for a horizontal) I'll have a bit of a think about things as it may be I can increase the stroke very slightly if I can accommodate a larger crank throw.
The valve chest doesn't have the cast part to take the free end of the valve rod
It will be a minor miracle if this thing ever works with all these mismatched parts and a drawing doesn't suit the parts I have ;)
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I did think about increasing the stroke, if you do so you will need to make sure the big end does not hit the bottoms of the standard, the trunk guide is long enough and that the conrod does not hit the ends of the trunk guide when at a steeper angle.
I have found the last of those to be the most common problem area when drawing up the 24series and also the big Tidman was very close so lots of adjustments to the cad drawing and turning the engine over on the screen to check clearances.
The later 2007 drawing has details of the valve rod guide ;)
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Thanks, I'll look into it before I cut the crankshaft.
Do you see any problem in not having the valve rod supported at the top ? I don't think the valve chest wall will have sufficient thickness to drill the required depth.
Edit - forget what I said, I see what you mean about the new drawing having a separate guide now :wallbang:
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I have copies of the No 4 drawings with the cylinder shown at 2" and 2 1/8". My No 9 Drawings show the cylinder at 2 1/8". The original cylinder casting has positions to allow the draincocks to either go at 90 degrees to the valve face or opposite the valve face to allow it to fit either No 9 or No 4 engine.
Maybe Stuart were told their later undersized castings were too small to make to their drawings ::)
Jo
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Jo that looks to be the same casting I have and is a 4 or a 9 in new money. :headscratch:
Just as a matter of interest how old was the casting kit you made your no9 from, what is the stroke length ?
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The stroke length is different on the No 4 and the No 9..... Even ones with the 2 1/8" drawings.
I had a similar problem with the 5A drawings: the Swan has slightly longer cylinders ::)
Jo
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Peter, what is the cast length of the valve chest as if that won't clean upto 2 1/4" its going to look a bit odd though there are ways around it.
Also watch your glands :o the new drawing has them with different hole ctrs and larger bore which would probably mean having to machine the smaller boss off of the cylinder casting to get back to the larger area one.
Bet you are wishing you made it from solid now :LittleDevil:
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At the moment the cylinder length is 56.64mm and the rough casting of the chest is about 56.15mm, admittedly I'll need to take a fine cut to the chest but the difference is small. If need be I'll mill a fine cut off either end of the cylinder.
(https://farm1.staticflickr.com/974/27386340417_9f5dd6cf75_z.jpg) (https://flic.kr/p/HJ39T4)
The covers are cast no 94 and 95 which presumably is a Stuart part no ?
(https://farm1.staticflickr.com/953/41355853035_1bb7b0c34e_z.jpg) (https://flic.kr/p/261tyhT)
I wanted to make the end covers today but to be honest I'm a bit stuck and need to think it through. The top cap hasn't any spare material to hold onto for turning, it's not the end of the world but it's the first time I've made a cylinder from a casting and I'd really like to do a decent job.
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Do you have soft jaws?
(http://img.photobucket.com/albums/v156/jasonballamy/Engineering/Vertical%2024/DSC02591_zpsyi8cly1m.jpg)
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I don't have soft jaws, how did you turn the outer diameter ?
I kinda thought about rough centring on the rotary table then drilling the 6 mounting holes to attach it to a temporary fixture in the lathe or even cutting the outer edge on the RT ?
You are right about making from scratch, if I made it from barstock I'd be posting a video of it running on the hot stuff by now ;)
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Use a pot chuck Peter.
You are right about making from scratch, if I made it from barstock I'd be posting a video of it running on the hot stuff by now ;)
I'll let my supplier know not to provide you with any more castings then ::)
Jo
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I'll let my supplier know not to provide you with any more castings then ::)
Jo
On a serious note, I'm happy with the quality of the castings. It was a bit tongue in cheek when I said I could cut from stock quicker ;)
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I don't have soft jaws, how did you turn the outer diameter ?
Well that's the joy of starting with barstock you have got a dirty great bit of bar to hold onto :LittleDevil: Turn OD and the spigot then saw off and do the other side.
(http://img.photobucket.com/albums/v156/jasonballamy/Engineering/Vertical%2024/DSC02590_zpswsahyn3g.jpg)
There are other ways to hold if you don't have soft jaws, 5C is one option on the spigot that is whats being used here to do the drilling
(http://img.photobucket.com/albums/v156/jasonballamy/Engineering/Vertical%2024/DSC02592_zps2yuxjz6c.jpg)
Or if your 3 jaw does not have a silly great chamfer on all the corners you can again hold by the spigot
(http://img.photobucket.com/albums/v156/jasonballamy/Engineering/Jowitt%20MkII/DSC00601_zpsued9mivi.jpg)
Another option would be to face off a scrap of say 1" stock and set aside then hold by the casting by its outside in your 3-jaw to face back the spigot and mating flange face. Then with it still in the chuck superglue on your scrap of metal and let it set. Then gently skim the OD of the scrap true which will give you a decent size chucking spigot for gentle turning of the OD and outside face
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Thanks Jason, you'd think makers of castings would add an bit of extra material for chucking purposes :headscratch:
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Quite a few of them do.
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Even Stuarts do, but it is normally only 2mm or so, plenty enough to machine the bottom of the flange. Yes as JBWelder says small diameter covers are often as not easier to turn from bar stock but where is the challenge in that :shrug:
And you still have to turn them over and hold them by the flange for the final machining. I think I mentioned pot chucks ::)
I like the challenge of using castings, each has unique learning opportunities which is all part of the fun :pinkelephant:
Jo
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Agree that it would have made a lot of sense to cast a short holding spigot, probably on the outer face.
Not quite sure what Jo refers to as a "pot chuck". I quite often make use of a suitable size block of MDF ( "Medite"), or a hardwood offcut held in the four-jaw, to machine awkward slices such as a cylinder cover. Does generally require a finished OD to be established first, though, and a reasonably flat back face on the workpiece.
Just turn a slightly undersize recess in situ and tap the component into the recess. Often helps if you remember to drill an axial hole through the MDF first, so that you can knock the item out of the holder when you're done! Dave
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I don't mind using castings .holding spigots still have to be cut of and the part finished.i have done these by holding by the cylinder spigot in the three jaw chuck but also by machining a recess in a scrap piece of material
steel or alloy ,a push fit not tight held with a live centre on a entered pad is enough to finish the od.
the next series of operations that are often the challenge and have to be thought of at the start.Getting location and holding can be difficult to finish if its a casting or bar stock.working from bar can be ok but just different problems to be thought about .
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Not quite sure what Jo refers to as a "pot chuck".
:headscratch: a selection of my Pot chucks... these have a wide slot in the side for machining ball handles. Basically they are a piece of steel turned up into a top hat that is used in a three jaw chuck. Think of them like collets or soft jaws but without all the expense :paranoia:
Jo
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Thanks for the suggestions guys and gals :)
I had a think about how to turn the top cover overnight and came up with this idea.
First job was to face off the bottom (inner) side, there was a domed recess on this side but I bored this out to create a shallow flat bottomed hole and turned the cylinder locating spigot
(https://farm1.staticflickr.com/898/42280958401_d619f24ee3_z.jpg) (https://flic.kr/p/27qdXTp)
With couple of bits of scrap I made a raised spigot and a centre drilled disc.
(https://farm1.staticflickr.com/962/41379096665_5721a60449_z.jpg) (https://flic.kr/p/263wFP8)
A drop of Loctite 638 secures the cover to the spigot and the drilled disc adds a bit of support
(https://farm1.staticflickr.com/878/42234276852_84417554aa_z.jpg) (https://flic.kr/p/27m6H67)
The bond was more secure than I expected so I was able to turn the top face without the centre support after turning the outer rim.
(https://farm1.staticflickr.com/945/41559791394_7afaf4d31f_z.jpg) (https://flic.kr/p/26juN4u)
Next job is to drill for the 4ba fixing holes, I try to avoid the turny table if I can but in this case it is going to give the most accurate result. A fairly crude arrangement with a rule in my milling vice ensures the port face is squarely postioned.
(https://farm1.staticflickr.com/957/41559768594_fb75af10b0_z.jpg) (https://flic.kr/p/26juFho)
(https://farm1.staticflickr.com/953/28407933098_3da23dde7c_z.jpg) (https://flic.kr/p/Khj5MY)
Halfway and it's looking ok :)
(https://farm1.staticflickr.com/971/41559722394_0d7daaafeb_z.jpg) (https://flic.kr/p/26jurxQ)
A bit more twiddling the handles and I arrive at this
(https://farm1.staticflickr.com/944/41559704834_40671871d4_z.jpg) (https://flic.kr/p/26jumk5)
(https://farm1.staticflickr.com/878/28407889288_4052c3937f_z.jpg) (https://flic.kr/p/KhiRLC)
I'll use proper studs later but for now bolts give me an idea of how it's shaping up.
(https://farm1.staticflickr.com/958/27410359727_9ed6204a8d_z.jpg) (https://flic.kr/p/HLafZ6)
Peter.
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Excellent!
:popcorn:
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That all looks very good Peter, and I like the "turny table" nickname !
Thanks Jo, if that's deemed to be a pot chuck then I have a tin full already: I made the ball handles for various bits of GHT tooling using the same gadgetry as in your photo, ( in my case, as outlined by GHT in his article long ago on making up these handles) . Dave
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Thanks guys :)
I dread using the turny table but it has its uses.
I wasn't really sure whether to machine the dome in the top of the cover or leave it just as the raw cast, I decided to keep it and just give it a rub with emery.
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boring out to a square recess increases the clearance volume at the end of the cylinder. should try to keep to a minimum.
How much metal is left between the two sides the corner of the recess must be closer to the recess on the other side.
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Hi John, I can see that keeping the inner recess small is a good idea but with a domed recess already cast in I've actually removed very little and the cover thickness at its thinnest is still substantial.
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The No4 design is quite poor when it comes to excess space as they show the top and bottom of the piston being recessed but unlike other engines that have the covers shaped to follow the pistons contour on the No 4 they are just flat.
A larger AF nut to retain the piston would easily compensate for the metal removed from the underside of the cylinder, if that was combines with an aluminium piston with no recesses you would have a better job all round.
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My intention was to use a cast iron piston but reduce the depth of the top recess, as long as the piston reaches within a mm or 2 at TDC I think things will be fine.
I can see it's not the same as comparing the compression ratio on an IC engine but I wonder if there is an optimum ratio in a steam engine ? Presumably the type of work and speed of the engine comes into play ?
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Presumably the type of work and speed of the engine comes into pla
Yes, that's why ones like the sawn, cygnet and 5A have a minimal void as they are more likely to be "worked"
Watch the balance as you are likely to already need a longer piston due to the cylinder length issue and without the recesses it will not be as light. Real engines often had hollow pistons to keep the weight down and promote smoother running.
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Thanks, once I have the bottom cover in place and properly bolted down I'll assess the situation before making the crankshaft or the piston.
I'm hoping this engine will be capable of running at a decent speed on say 60psi of steam as I want it to be able to do some light work. A balanced crankshaft as mentioned earlier in the thread is probably going to help
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A larger nut will compensate for the extra space .The piston will be heavyer when made longer adding to the reciprocating mass.the no 1 has a 2 piece piston with a hollow in the centre ,would that be worth doing?
the top and bottom faces kept flat.
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Thanks John, at the moment I'm still thinking about how to proceed.
Has your no4 got a cast iron piston? I'd expected to do that for this engine though I expect a lighter material may improve high speed running. My hope was to use a standard size piston in a slightly longer bore and increase the stoke slightly but as Jason said that might not be possible.
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Leave the stroke alone Peter, by all means give it an ali :facepalm: piston which is longer than as drawn by the additional cylinder length. Then increase the piston rod length by the additional cylinder length, beyond the shoulder where the piston goes up against so it goes through the piston and there is space for the nut..
Keep any changes simple :)
Jo
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Thanks Jo, I did consider aluminium for the piston but isn't that too soft ? will aluminium last if I want the engine to be able to perform light work ?
I just kind of assumed if Stuart use cast iron pistons in the real thing then it must be proven to work well.
If I do alter the stroke it will be small (the cylinder is only 6mm longer than the plan), so I'd probably only add about 2mm or so the crank throw and slightly alter the piston shape to reduce the end volumes as John mentioned.
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One of the biggest exponents of aluminium pistons for use on traction enginesi s Terry Baxter, he rallies his 4" engine most weekends during the summer and it will run all day and then spend the evening outside the bear tent generating (it's a showmans engine with full set of lights) and it runs so smoothly that there is barely a ripple on his pint if it is stood on the canopy.
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it will run all day and then spend the evening outside the bear tent generating
Is that the polar bear tent or the grizzly bear tent ? ;)
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You can tell I don't drink!
Just looked back at a couple of terry's posts and the same piston has been in the engine for 15yrs
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I haven't done any machining today but have just taken a few rough measurements, it appears that the port spacing won't allow an increase of stroke like I'd hoped, I may just mill a little off each end to shorten the entire cylinder and reduce the void space at either end.
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it appears that the port spacing won't allow an increase of stroke like I'd hoped,
There are ways around that so that the ports are not covered by the piston at the ends of it's stroke or the longer piston is stroke kept as is.
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yes the piston in all my stuart turner engines are cast-iron .
The temptation to alter the stroke to use the longer cylinder ,the problem is the trunk guide and the base restrict
how much room for the big end to fit .
I would not make to many changes at this stage.
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Cheers John :)
I'm about to start on the bottom cylinder cover but completely stuck on a thread issue and hope someone can help out.
The cover calls for a 1/2" x 26tpi threaded hole to accept the piston rod gland, I don't have any taps and dies in that size and would rather make mine metric anyway so I was looking at M12 threads.
I'm now baffled as to which M12 taps I need to be a close approximation. I can see that 26tpi is teeth per inch but what are the tpi on M12s ? As I understood it M12 x 1 means the depth of thread is 1mm ? Does it also mean 25.4 tpi ?
Does M12 x 1 sound like a reasonable alternative as I don't want to order something unsuitable :(
(https://farm1.staticflickr.com/953/41598813114_bc89c6707e_z.jpg) (https://flic.kr/p/26nWMRL)
I did consider making a bolted on stuffing box like a no9 engine (my casting cover has an oval boss for that purpose) but that will make it difficult to adjust in the trunk guide
Thanks
Peter.
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Peter you need a fine thread for that so that you can get the compression on the packing right .... M12 is rather too coarse. :(
Jo
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Thanks Jo, I have just 1 M12 tap that came in a set - it is M12 x 1.75 and is very coarse so I looked at M12 x 1 - isn't that reasonably fine ?
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The 12mm diameter by 1mm pitch will do :ThumbsUp:
Jo
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Metric coarse is the generally used one if nothing is specified this is 1.75mm pitch (14.5tpi), you can then get metric fine which would be 1.5mm pitch (16.9tpi) and then you can get other pitches. M12 x 1.0 would be the closest to 26tpi and is 25.4tpi in old money.
An option that may be more useful in the future would be 1/4" BSP, this is approx the right dia but slightly coarser at 19tpi, often used for plumbing in engines.
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Thanks I'll order M12 x 1.
For now I work on the 10v and try to get the cylinder made :)
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Until I have some M12 taps I've decided to do a bit more with the 10v and have now largely completed the trunk guide.
I haven't yet got a faceplate for my lathe so chose to do the guide on my mill, it doesn't need much doing but I was given the casting and it seems to be a good quality one so I didn't want any disasters.
With the top cleaned up and sitting square on the milling table first job was to level off the feet.
(https://farm1.staticflickr.com/970/41425160945_0ce8fc7eff_z.jpg) (https://flic.kr/p/267AM7R)
Centering the bore the bore under the spindle, ready to face the top and cut the bore.
(https://farm1.staticflickr.com/952/42326560591_e1b997c1d4_z.jpg) (https://flic.kr/p/27ufFQ4)
This cheap and cheerful boring head seems to perform well and as the tool is pretty much on the centreline I was able to rotate at a decent speed to finish cut.
(https://farm1.staticflickr.com/878/42279531672_3b1812457e_z.jpg) (https://flic.kr/p/27q6DLC)
Once bored out to 16mm it's time to run the mill in reverse to take a few small cuts around the top and finish with a 35mm dia surface.
(https://farm1.staticflickr.com/961/42326525761_d74cb786b0_z.jpg) (https://flic.kr/p/27ufvtx)
I'll drill it later but otherwise it is pretty much done :)
(https://farm1.staticflickr.com/954/42279490582_b04f3aa854_z.jpg) (https://flic.kr/p/27q6ryb)
(https://farm1.staticflickr.com/974/42279475802_bc7596a097_z.jpg) (https://flic.kr/p/27q6nam)
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Looks good peter
Just watch those boring heads when running in reverse as the body can unscrew from the MT/R8 shank
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Thanks, I'll bear that in mind next time :)
It's not a bad boring head for the price but the allen screws holding the adjustment are rubbish (they must cost ten pence a ton), any suggestions on who sells decent quality replacements that don't round off ?
With a bit of luck I'll get the cylinder part done tomorrow.
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I did my little PM “coke bottle” engine on the mill the same way :ThumbsUp:. On the grub screws in the boring head: Dave Otto wisley advised me to just nip up the two outer ones like you would be setting gibs, and to just forget about the middle one. A decent boring head, with backlash removed, will hold it’s diameter pretty darn good. Yes, high quality screws will make the tightening easier, but, you’ll probably have to buy 50-100 of them to just use 3 :facepalm:. and they don’t need tightening that much anyway. That’s my two Confederate pennies worth :lolb:.
Cletus
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It's the tool holding ones that are rubber, probably 5/16whit but may be M8
As whisky says I keep the god ones nipped up and never touch touch them when adjusting size
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Thanks, the screws that are rubbish on this model are the 3 that retain the dovetail, the heads are so soft they just round off. I haven't measured them properly yet but they look to be M5. I have loads of M5 but mine are also just cheap hardware quality and no better than the ones supplied.
I just thought you guys may know of somewhere that supplies small quantities of good quality fixings for tool use.
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Question...it wasn't clear to me when you faced the top. Was that done before doing the feet?
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Question...it wasn't clear to me when you faced the top. Was that done before doing the feet?
Hi Carl, I machined the feet square before facing the top. In the 1st photo with the guide upside down I have only filed the top flat enough so that it sits flat on the mill table and is properly vertical. Once I was happy the feet were level and perpendicular to the (unmachined) bore I turned it the right way to face the top and bore the centre at the same setting.
It's the first time I've done this so I'm not saying it's the best way but it seemed to make sense to me :)
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Question...it wasn't clear to me when you faced the top. Was that done before doing the feet?
Hi Carl, I machined the feet square before facing the top. In the 1st photo with the guide upside down I have only filed the top flat enough so that it sits flat on the mill table and is properly vertical. Once I was happy the feet were level and perpendicular to the (unmachined) bore I turned it the right way to face the top and bore the centre at the same setting.
It's the first time I've done this so I'm not saying it's the best way but it seemed to make sense to me :)
Thanks. It's the way I would have done it...but not from an experienced point of view...just (as you say) what would seem to make sense to me.
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looks like success with that part looks good.
I have not had a milling machine to do them like that I and set them in the four jaw chuck and face plate to do the top face and bore .I can see were the out side of the casting round the trunk is .i want the bore to be in centre of the casting not in the cored hole if it is not in the centre.
The grub screws are probably metric ,the key needs to be in good condition and right size see the key fits the socket then don't over tighten .
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Thanks John, I did wonder about the accuracy of taking a reading from the rough cored hole but it did look like the original bore ran true.
Obviously I couldn't get a non fluctuating reading on the coax indicator in a cast bore but with care I could get to what I thought was the centre enough to try a very fine first cut :)
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The end result looks good .if you checked the hole was central at top and bottom you can't do any better.
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I've now turned my attention to making the cylinder for the 10v while I wait for my M12 taps and die to arrive. I want to make it from a cast iron block to look similar to a proper Stuart cylinder, I won't be able to make an exact copy and I do intend to add cladding so something reasonably attractive is my goal.
A piece of 40mm square cast iron looks to be just big enough
(https://farm2.staticflickr.com/1725/40539394100_ff61b35f7a_z.jpg) (https://flic.kr/p/24LjZuG)
Incidentally it turns out the Stuart casting I bought as a full set has an undersize cylinder - the cast block is marked at the required diameter according to Stuart as is the trunk guide top but it is clear the cylinder casting is significantly undersize.
(https://farm2.staticflickr.com/1753/27476570037_778cc36187_z.jpg) (https://flic.kr/p/HS1B1a)
The wiggler and dial indicator are simple way to get the centre positioned accurately
(https://farm2.staticflickr.com/1726/27478902277_81f0f164d8_z.jpg) (https://flic.kr/p/HSdyic)
With one end turned to match the trunk guide it is on to turning the 16mm bore. (it may look the wrong size but it just the way I'm holding it ) :)
(https://farm2.staticflickr.com/1721/41446160155_e132e7d153_z.jpg) (https://flic.kr/p/269spsc)
(https://farm2.staticflickr.com/1750/42348506841_d14e0abcb4_z.jpg) (https://flic.kr/p/27wcaFF)
With the part now turned around it's just a case of centering with the coax indicator and turning a matching end flange
(https://farm2.staticflickr.com/1758/41639960914_ff3e343128_z.jpg) (https://flic.kr/p/26rzFEA)
(https://farm2.staticflickr.com/1749/40555425400_b07422e54d_z.jpg) (https://flic.kr/p/24MKa3q)
That completes the lathe work for the cylinder and takes me to this point, I should have mentioned earlier but the bore is intentionally off centre to allow for the port face
(https://farm2.staticflickr.com/1752/28489548758_3a3073b462_z.jpg) (https://flic.kr/p/Kpwohw)
I'll probably get the milling done on the sides and the ports drilled tomorrow but for now I think it is starting to take the shape of an engine :)
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Cylinder should be smaller dia at the flange than the covers and standard this is so that when the cladding is applied it comes flush. Just like the muncaster.
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Cylinder should be smaller dia at the flange than the covers and standard this is so that when the cladding is applied it comes flush. Just like the muncaster.
Ah - I didn't realise that :facepalm:
That's a pain the backside, I'll need to take a bit more off the flange diameters :(
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Decide what you will use as cladding and reduce by 2 x thickness.
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I had thought about just the metal sheet as used in Stuart engines, any idea what they use, what thickness etc ?
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It used to be blued steel but they now supply a black anodized aluminium 0.5mm thick, easy enough to spray up thin aluminium of that sort of thickness or slightly more.
Also make the port face smaller than the valve chest by the same amount so it gives you a nice edge to stop the cladding against
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Ok thanks, I'll order a sheet. I had thought about wood cladding the no4 but if I have a sheet of material the option is open.
The brass to make the bearings of the no4 has just arrived, I did think bronze may be a better option but wasn't able to find any square of a suitable size without paying the earth so went for brass. I'll make a 12mm dia crankshaft so I'm hoping over a reasonably large contact area that brass wont wear out quickly :headscratch:
Edit - thanks for mentioning the valve chest, things like that are easy to overlook when you haven't done it before :)
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Peter, I was thinking that you will end up with a shorter valve chest as you have carried the flanges all the way round, have you checked to see if you will have enough space for the valve and it's movement?
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Thanks Jason, I hadn't noticed but you are right - this one for the scrap bin :(
I'll start again with a new cylinder
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This may help but you may need the Roundy, roundy" table,
http://www.modelenginemaker.com/index.php/topic,4438.msg87653.html#msg87653
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Thanks Jason, I've partly done the bearings for the no4 while I think about how best to tackle the cylinder. When I've finished the bearings I'll study your photos and see if I think I can manage something better at the 2nd go.
I could do with more practice at the rotatey twisty table :)
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I didn't take any photos of the making of the no4 bearings as I used the same method as the 10v earlier
Without any 12mm rod to check the alignment this 10mm suggests everything will be ok.
(https://farm1.staticflickr.com/901/41485188145_159e6fe6c3_z.jpg) (https://flic.kr/p/26cUr7z)
My only slight concern is they may have a bit of the 'Legoland' look. I'll probably make humpback tops to soften the appearance a bit.
(https://farm2.staticflickr.com/1730/40579574150_cce95fd536_z.jpg) (https://flic.kr/p/24PSVCb)
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The more I look at the bearings the less happy I am :(
They are far too boxy and Lego like, for now I think I'll get the crank made while I think of the way forward.
I'm open to suggestions if anyone has thoughts on how to soften the look and make them more realistic :headscratch:
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As per my PM reduce to 22mm square, thin flanges, round over the top half. This allows caps like a Stuart.
You could also do as your last message and turn the whole thing down and use an insert in the lower half flange could be all round or just rounded at the top
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Thanks :)
I really need to get some drawing software so I can do that kind of thing.
I'm looking at doing something like your suggestion but I'd like to have the end flanges fully circular if they will still cover the inner square portion.
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Drawing software says you would need a 26.87mm dia flange to cover the rectangular hole ;)
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Thanks, that's a prime example why software would help. When you are just imagining things and trying to build from a plan in your head it doesn't always turn out right.
Looks like a job for the turny table tomorrow ;)
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Although the no4 bearing blocks still need a bit more cosmetic work I decided to tackle the bottom cylinder cover and piston next. I did take a few photos of machining the cover but somehow seem to have deleted them before uploading to Flickr. Anyway it was a simple turning job from a casting I bought followed by cutting a M12 fine thread to accept the gland nut.
The 2 taps and the die I bought for the job were only cheap ones (I think I paid about £11) but I was quite impressed by look and feel of them and they did the job :-)
(https://farm2.staticflickr.com/1775/42890699942_b2dc2d1bc4_z.jpg) (https://flic.kr/p/28m73NA)
Although this thread is aimed at beginners it's difficult to know how much detail to show and when to be brief, I guess most beginners can turn a piston but I did take a few photo along the way. My initial intention was to make the piston from cast iron but after a bit of advice and a bit of thought I settled on aluminium. I've never used aluminium pistons before so we'll see how this performs on the hot stuff later but the lightness may be useful in high speed running ?
I like to turn the piston on the rod it will be coupled to, it is 7mm rod threaded at 2ba with a centre for stability.
(https://farm2.staticflickr.com/1820/42221045054_21a2b47cb5_z.jpg) (https://flic.kr/p/27jVTJE)
Creeping up on the final diameter it's a nice close fit :)
(https://farm2.staticflickr.com/1834/42890602972_dd8f8a2810_z.jpg) (https://flic.kr/p/28m6xYG)
I think it may have been in Brians Oscillator build thread that the subject of graphite yarn piston rings briefly came up so for the benefit of those who have never tried it this is how I do it. The yarn for this piston is 1/8" sq so with a parting tool I just gradually cut a piston groove until the yarn will just fit width ways but to a depth that it sits wider than the diameter very slightly.
Here I am getting close to the size of groove I want
(https://farm2.staticflickr.com/1832/42940136901_c6503e6402_z.jpg) (https://flic.kr/p/28qtqFX)
A bit deeper then cut to length and this looks about right
(https://farm2.staticflickr.com/1832/42221084414_7d5aa637f9_z.jpg) (https://flic.kr/p/27jW6rh)
Soaking the yarn in oil and packing it down it's possible to get a good seal around the piston, the ring is in place here and a couple of loose strands / graphite can be seen. It is a good seal though and slides smoothly in the bore :)
(https://farm2.staticflickr.com/1835/28070735597_99cefe5a3d_z.jpg) (https://flic.kr/p/JLvRHX)
I'm now at this stage
(https://farm2.staticflickr.com/1784/42940100531_853bacf79a_z.jpg) (https://flic.kr/p/28qteST)
(https://farm2.staticflickr.com/1823/42940087061_99ba41bca8_z.jpg) (https://flic.kr/p/28qtaSD)
With the covers in place I'm happy with the suction effect so hopefully the finished engine will have a bit of oomph :pinkelephant:
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Although this thread is aimed at beginners it's difficult to know how much detail to show and when to be brief, I guess most beginners can turn a piston but I did take a few photo along the way.
I think detail and discussion is good regardless whether it's aimed at a beginner or not.
Beginners read a lot.
And I learned a few things from this post. :ThumbsUp:
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Thanks Carl, it's good to know you are still following along :)
I've largely got the crosshead made and would like to machine out the vertical slots in the trunk guide next (my guide is a fabricated one as hasn't got the slots cut yet).
As it would normally have been a cast item the plans I have don't show the slot dimensions. Admittedly the dimensions aren't critical but I'd like my engine to look very similar to the original if possible so if anyone has a No4 they can measure I'd be grateful.
Many thanks :)
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The slot on mine is 3/4" wide there is 5/16 + of metal or 5/16" thick of metal at both ends .
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The slot on mine is 3/4" wide there is 5/16 + of metal or 5/16" thick of metal at both ends .
That's great thanks John :)
I have a 16mm mill so that should give me something very close and keep the semi circular ends to the slots.
19mm would be better but I don't think my milling set up will take larger than 16mm but to preserve the radiused ends to the slots with an under sized cutter will be a pain.
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you could use a simple boring bar with a tool set to bore 3/4"at the ends
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you could use a simple boring bar with a tool set to bore 3/4"at the ends
I have a boring head and rarely use it so kinda forgot I have it but you've got me thinking that it ought to do this sort of job perfectly.
Cheers :)
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Or just drill 3/4" at each end and then use a smaller cutter to do the sides of the slot.
Boring head is best done with a series of plunge cuts rather than trying to move the work against the spinning cutter
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Thanks Jason,
I was kinda thinking of opening out drilled holes at either end of the slot with the boring head then just use a standard milling cutter to link them.
Now that John has offered suggestions it's pretty obvious to see there are numerous ways to achieve the desired result but it's something I'd never really thought about till now and with boring head getting little use I overlooked it completely :headscratch:
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Peter -
have just read this whole thread up to this point.
Your build has been an amazing journey so far and not without its challenges. As someone who is not even a beginner yet I am inspired by what I see here...
Can't wait to get started on some basic engines once my boiler is done!
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Cheers Gary :)
After a bit of a break from building these engines to soak up the UK sunshine I now want to resume building, I've decided to fabricate a crankshaft rather than turn from solid as I had initially intended.
So before continuing it's question time - I'd like the no4 engine to be reasonably robust with the possibility of powering a pump when running on steam so I want to secure the flywheel with a keyway. I don't have a broaching kit so I'm going to try with a parting tool in the lathe to cut the flywheel slot and mill the slot in the crankshaft.
I've never cut a keyway before so can anyone offer a few guidelines as to the width and depth of the slots? My crankshaft is 12mm dia and the flywheel will be about 4.5" dia x 1" wide. Do the slots usually have a square profile (the same depth and width) ? Should the 2 slots be of the same depth ?
Many thanks :)
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The combined depth of the slots is generally equal to the width so a square section key will fit.
For what you are doing and to make it easier to plane it out on the lathe 3/32" would be a reasonable width, if you want to put a head on it to look like a gib head key the 4 x 2.5 is a standard size keysteel.
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Thanks Jason, now that I've had another look at the wheel casting I'd intended to buy it looks to have a hub too small to take a 12mm shaft and a keyway :(
https://www.ebay.co.uk/itm/Model-Making-Steam-Engine-Cast-Iron-Fly-Wheel/173405783593
Luckily I haven't bought the wheel yet but struggling to find anything else, there must be something out there about 4.5" dia x 1" thick that is cheaper than the £44 Stuart want after VAT postage :o
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I think I have one of those, will go and check the size of the boss
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I think I have one of those, will go and check the size of the boss
That would be great thanks, the alternative is the curved spoke casting that the Muncaster engines have - one of those would be the right size but I'd prefer straight spokes for this style of engine.
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Having taken a bit of a break from these 2 engines for a couple of months I decided it was time I got my arse in gear and do a bit more, otherwise I'm in danger of becoming an armchair engineer who criticises everyone elses work but never make anything of my own. ;)
Turning my attention to the no4 (the big un) a simple turning and threading job on a piece of brass gets the crosshead to fit nicely in the bore of the standard. I'll machine flat faces and drill it once I have cut slots in the standard and decided how I'll make the con rod.
(https://farm2.staticflickr.com/1963/31469349788_3f9c41c6e0_c.jpg) (https://flic.kr/p/PWQDjm)
(https://farm2.staticflickr.com/1951/45293874892_0be441a4c5_c.jpg) (https://flic.kr/p/2c1sWZs)
The next logical step seemed to be the drilling and tapping to secure the cylinder to the standard. Owing to the shape of both parts it is necessary to drill the standard from above and the cylinder from below so they can't be drilled at once (with the cylinder cover). I have a rotary table but my mill doesn't have DRO so I'm faced with either trying to position things very accurately then working with the mill handwheels to drill the parts independently and hope they match up or take the cheats way out by using double sided sticky tape :embarassed:
I'd like to have used the more accurate handwheel method but I think at times common sense is needed. The position of the holes is largely non critical as long as they line up, a new casting for a cylinder or a standard could make a mistake costly. Ok, that's enough of justifying why I'm going to cheat, but this was how I tackled the job.
With the cylinder centred on the turny table it's now a case of dialling out to a 23.5mm radius then rotationally lining up with a line scribed parallel to the port face.
(https://farm2.staticflickr.com/1919/44430524305_0d12183d52_c.jpg) (https://flic.kr/p/2aGb3Wv)
11.25 turns on the hurdy gurdy rotates the part 45o for the first hole.
(https://farm2.staticflickr.com/1918/45294065182_fcf7f66e30_c.jpg) (https://flic.kr/p/2c1tVyj)
A bit of double sided stick tape is amateurish but it will hold the cover for drilling.
(https://farm2.staticflickr.com/1975/31469506168_0813bd02e9_c.jpg) (https://flic.kr/p/PWRrNy)
Despite how things look in the photo the holes are evenly spaced and they line up in any rotation :)
(https://farm2.staticflickr.com/1919/44620949224_83f9c8bf19_c.jpg) (https://flic.kr/p/2aZ12CL)
Now for the cheaty bit, with the cylinder and cover marked so the holes line up I was able to position the cover to the correct orientation against double sided tape on the standard ready for drilling. The cylinder has rotated in the photo but the cover is where I want it.
(https://farm2.staticflickr.com/1974/30404554607_474784a36c_c.jpg) (https://flic.kr/p/NjKhNK)
With one hole drilled and the cover bolted its now just a case of drilling through to a 4ba clearance size.
(https://farm2.staticflickr.com/1959/31469579928_44e2ddaaf3_c.jpg) (https://flic.kr/p/PWRPJh)
Not rocket science by any means and maybe a bit amateurish but I'm happy to say it all lines up nicely when bolted together
(https://farm2.staticflickr.com/1913/31469602828_474c1e7cae_c.jpg) (https://flic.kr/p/PWRWx7)
Peter
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Good to see you back at it.
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Thanks, I'm pleased to get back in the saddle, I needed a bit of a break from it but feel in a better frame of mind now :)
I've got a 3" Southworth pump casting kit on order so was thinking of doing a build log in the forum, I'm led to believe they can be fiddly to build but I could do with one for a small boiler I recently bought and the castings are cheap so I thought I'd give it a try
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Onwards and upwards I've now got a bit further with the no4 engine by making the crankshaft, I'd really like to have a go at turning one from solid bar but still lack a bit of confidence at turning the offset shaft between the webs accurately so a fabricated crank it is ::)
Making a fabricated crank is straight forward but as this build log is aimed at less experienced machinists or those with limited tooling I thought it may be of use showing in some detail how I do it, so here goes -
I started out by squaring off 2 pieces of mild steel to the required width of the webs followed by drilling and reaming the holes, in this model Stuart use 7/16ths shafts for both the main shaft and the offset but with the barstock I have to hand I'm making them 12mm.
(https://farm2.staticflickr.com/1911/45451771581_105ed4f5b5_c.jpg) (https://flic.kr/p/2cfqdba)
If you haven't already made a vice stop it's worth doing as it makes milling and drilling multiple components at the same setting easy.
(https://farm2.staticflickr.com/1966/44536999725_cb8c945e1a_c.jpg) (https://flic.kr/p/2aRzLnB)
Although both shafts are 12 mm dia I've driiled and reamed the offset at 10mm, it's not really essential but I find a step in the pin diameters helps when assembling the parts and ensures the correct web spacing.
(https://farm2.staticflickr.com/1956/45399965712_90ba5990c5_c.jpg) (https://flic.kr/p/2caQG6w)
Next job trim off a bit of the waste to reduce the amount of interrupted cutting in the lathe
(https://farm2.staticflickr.com/1930/45451939301_c19a514276_c.jpg) (https://flic.kr/p/2cfr52T)
To radius the ends I made a close fitting mandrel.
(https://farm2.staticflickr.com/1917/31576582818_eb9b883573_c.jpg) (https://flic.kr/p/Q7jeXG)
That seemed to have the desired effect so the other end was done the same way
(https://farm2.staticflickr.com/1909/45451905171_1a0fb52f30_c.jpg) (https://flic.kr/p/2cfqTTr)
That takes me to this point (the holes are still full of oil and swarf but they are reamed)
(https://farm2.staticflickr.com/1950/44727038844_d3146de939_c.jpg) (https://flic.kr/p/2b9nLo9)
My 3 jaw chuck has a bit of run out and wont give the necessary accuracy to turn the crank pin so it's on with the 4 jaw and centre it properly to turn the 10mm dia stepped ends from the 12 mm silver steel rod.
(https://farm2.staticflickr.com/1942/44536927335_bd1e27108f_c.jpg) (https://flic.kr/p/2aRzoRv)
Satisfied that the parts fit together nicely they were glued together firmly secured using Loctite 638 high strength retaining compound.
(https://farm2.staticflickr.com/1963/30511202257_24e62cbc52_c.jpg) (https://flic.kr/p/NuaTrk)
Whilst there are decent sized mating surfaces for the Loctite to bond to it makes sense to add pins for additional strength, I've opted for 2.5mm steel (with hindsight I'd wish I'd done 3mm) I'm never sure whether these pins are meant to pass right through the shaft and back into the web but in this case they go about 9mm into a 12mm shaft.
(https://farm2.staticflickr.com/1930/45451791731_484b95ed51_c.jpg) (https://flic.kr/p/2cfqjaz)
The pins will be secured with Loctite 638 then filed flush.
(https://farm2.staticflickr.com/1956/30511185167_a8520537f6_c.jpg) (https://flic.kr/p/NuaNmF)
A simple job of milling out the waste centre shaft should pretty much complete the assembly.
(https://farm2.staticflickr.com/1976/43634598220_750960c388_c.jpg) (https://flic.kr/p/29tQHQY)
A little bit of cleaning up gives me this finished part.
(https://farm2.staticflickr.com/1966/44536861625_50da7e4439_c.jpg) (https://flic.kr/p/2aRz4jz)
(https://farm2.staticflickr.com/1972/31576457398_24c816467a_c.jpg) (https://flic.kr/p/Q7iAFh)
Nothing particularly exciting, but I'm happy with the result it sits nicely in the bearings and doesn't have any run out :)
With the piston / crosshead assembly already in place it makes sense to next make the con rod, I tend to struggle with making them but I'm eager to get to the point where I can see how the piston and crankshaft operate once coupled together.
Peter
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Very nice looking crankshaft, Peter! Looks like it should do the job quite well :ThumbsUp:
Kim
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Thanks, it has been left to cure overnight and seems to have bonded well so hopefully it will have the necessary strength. :)
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A short update today but a bit closer to the goal of a finished engine
I'd like to get the con rod machined and in place this week but as this engine is a hybrid of part castings and part barstock some of the dimensions differ very slightly from the original Stuart plans. I'm making the parts based on what fits rather than rigidly sticking to drawings so before making the con rod I'd like to be able to see where the crosshead lies then machine the rod accordingly. So with this in mind it's time to mill out the trunk guide slots.
It's a bit of an irregular shape but using 4 clamps and a bit of packing I settled on this set up, I wanted a secure hold but didn't want to risk distorting the central bore and this seemed to fit the bill.
(https://farm2.staticflickr.com/1902/43679731830_68d682799a_c.jpg) (https://flic.kr/p/29xQ3uE)
I guess there a numerous ways to tackle this but I find it easier to remove most of the waste material by drilling and keep the milling for the final stages.
(https://farm2.staticflickr.com/1951/45445527902_79d0a712fe_c.jpg) (https://flic.kr/p/2ceSd9w)
A 10mm mill opens out the slot.
(https://farm2.staticflickr.com/1973/30556557307_b9454bf12d_c.jpg) (https://flic.kr/p/NybkUX)
John Mills in an earlier post measured the width of the slots on his engine at 3/4" (19mm) so I expected to have to use a boring head to open out the end radii but after going through with a 16mm endmill I decided to stop there. They look about the right size now but I can always open them out later if need be.
(https://farm2.staticflickr.com/1968/45445478652_8769461790_c.jpg) (https://flic.kr/p/2ceRXvo)
Although a bit undersize I'm happy with the result, as long as I have access to the piston rod gland nut and crosshead pin I see no reason to alter things.
(https://farm2.staticflickr.com/1944/45496427021_1daf976163_c.jpg) (https://flic.kr/p/2cjn5Fx)
A bit of emery to remove burrs from the bore and the crosshead slides nicely :)
(https://farm2.staticflickr.com/1924/30556505067_64e882c265_c.jpg) (https://flic.kr/p/Nyb5og)
That paves the way to make the con rod this week and see how the whole assembly turns over.
Peter
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Hi all,
While I decide how best to make the con rod I thought I'd have a go at making the exhaust gland, this is the first time I've dealt with castings so I could do with a bit of help. At the moment I have the cylinder block milled flat and drilled (the hole is central to the larger ellipse shape) at first I kind of assumed I only need to mill the smaller ellipse and make a brass gland to match but now I think I need to mill as far as the larger ellipse then make the gland to match that. Is this correct ?
If I do mill down to the larger profile is there any simple way of getting the gland to match, I can't see how I'd be able to machine the outer profile with the gland in place so I'm assuming it's a case of hand filing it ?
(https://farm2.staticflickr.com/1959/44600473535_0ef86ac284_c.jpg) (https://flic.kr/p/2aXc5VD)
I'd be grateful for a bit of help, thanks :)
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Hi Gas Mantle,
A great build, I have been following with interest.
First, a minor point of terminology, I suggest you are talking about flanges, a gland is the term generally applied to the soft packing arrangement which prevents leakage where a sliding or rotating shaft passes through the pressure wall. The stem of a valve, your valve rod and piston rod are all sealed by a gland.
But to answer your question, as in full sized piping systems, you can do whichever you like. Some flanges are smooth metal to metal, but most have a gasket which fills the microscopic irregularities of any surface if you look at it with high enough magnification. Or you can machine grooves to confine an o-ring, perhaps in one side only. You can even make loose flanges to use instead of nuts with the common tube tails.
The gasket has to be squeezed tightly between sufficiently smooth metal surfaces to ensure a seal, and that is the job of the bolts.
Low pressure piping gaskets are generally full face, which means they are the same outside size as the flange and have holes for the bolts and the flange has a flat surface to suit, but higher pressure systems have a smaller diameter raised face for the gasket face, which is totally inside the bolts so the gasket does not have bolt holes. The smaller diameter of the raised face allows the bolts to create higher pressure over the gasket to squeeze it as required to seal against high pressure. And the raised face on each flange plus the gasket thickness mean there is a small gap between the flanges at the bolt circle so the bolts can use the elasticity if the metal to slightly cup the flanges to apply maximum pressure to the gasket. A frightening thought when the flanges are high tensile forged steel over an inch thick!
So make a raised circle around the steam passage (just inside the bolt holes) very smooth, make a simple washer shaped gasket from oiled thick brown paper or other thin gasket material, and squeeze the gasket between the flanges to make it pressure tight. Or you can make a full elliptical smooth surface and make a full face gasket.
That is the full size practice, I will leave it to others to say what they find easiest to replicate in model sizes, but my observation is that most use the full face style. I generally use nuts and tails, as small flanges are a bit fiddly.
MJM460
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Hi again Gas Mantle,
On thinking a bit further overnight, (it is now morning here), I realise that I should have added that the flat face design of flange is mainly used with cast iron flanges, so perhaps more in line with prototype for historical steam engines. Because cast iron fails in a brittle manner, the bending of flange edges by bolt tension is not a good idea. The full face gasket design makes the whole thing a compression joint, so less likely to crack the iron flanges.
On your specific question of detailing that casting, would it be possible to just machine the actual gasket sealing face and leave the outline as cast? If the matching pipe flange is just slightly larger, the casting outline will hardly be visible.
From the model making point of view, I see the most difficult part as lining up the bolt holes in the matching pipe flange. There is not much tolerance on orientation, so you need one of Chris's amazing soldering jigs to keep everything in place. The flanges can be made square in the end of a tube by recessing the tube into a small socket on the back of the flange, but the orientation of the bolts is more difficult. Alternatively use a tail type tube end with a loose flange to allow the flange bolt holes to be rotated to suit. A longer steam pipe with at least one right angle bend will also allow some little bending of the tube to line up the bolt holes. Actually studs threaded full length are used in the industry I come from, rather than bolts, but the holes are still called bolt holes.
I hope a little information from full size is helpful. I am looking forward to seeing what you decide.
MJM460
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You don't really need to worry about shaping the flange to match the larger surface as the cleading will cover it and be cut to the flange's outer shape. I would mill down until the flange mounting face is flush with the edge of the port face which will give a nice flat surface for the cleading a shown in yellow. The current castings don't have the smaller raised oval shape that your older castings do.
Lining up stud holes should not be a problem if you build as per drawings and just screw the pipe into the flanges tapped hole. If you want to hard solder it then you will need to make sure it solders into the correct position.
Being bronze there is no risk of cracking the flange so you could add a recess for an O ring, or just use a thin paper or thinner still liquid gasget
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if the faces are machined flat as jason says there should be no problems.on the engines i have built i have not
cut gaskets often not even liquid gaskets and don't have problems running on steam. liquid jointing would be good
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Thanks guys, that's great. I must admit I hadn't considered milling down to the flat face but it makes sense now you mention it. I was kind of expecting to have to file a matching flange by hand but that seemed a bit of a messy way of going about things.
As for the con rod it seems from the plans that in a real Stuart engine it would be a single component made from brass (albeit with a split bearing), I think I'd rather make a steel version with separate brasses so intend to give that a go next then make the flange :)
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It is a soft gun metal casting, you will be better of with a steel one with split bronzes. Something like the Muncaster will do fine.
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Thanks, something similar to the Muncaster is my intention. If there is one part of making steam engines I dread its the con rod / bearing assembly I always struggle but want to get it at least roughed out today.
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I've being putting off making the con rod for a while but I'm not going to have a working engine without one so I've spent the last couple of days at it. In the past I've struggled with these components so I wasn't expecting miracles with this one :(
To start off I silvered soldered matching brass blocks that will form the split bearings.
(https://farm2.staticflickr.com/1963/31694653048_3468e5e1f3_c.jpg) (https://flic.kr/p/QhKo8j)
I'm wasn't sure if the trunk guide is slightly thicker than a proper Stuart casting but there doesn't appear to be a lot of room and it's not helping things that my crank pin at 12mm dia is slightly larger than the plans specify. Although I can partly use Fusion 360 I'm not yet sure how to use it to work out clearences so it's a bit of guesswork and hope for the best.
(https://farm2.staticflickr.com/1929/30626136977_8189df193e_c.jpg) (https://flic.kr/p/NEjXwr)
This block will be the bottom keeper and it is becoming apparent that increasing the crank pin dia to 12 mm isn't leaving much room to drill for the 5ba bolts.
(https://farm2.staticflickr.com/1976/45567325141_8c1d1cd579_c.jpg) (https://flic.kr/p/2cqCsdV)
I chose to drill the 3 components individually using a vice stop then use a spare drill bit to hold the parts ready to drill the 2nd hole in 1 go.
(https://farm2.staticflickr.com/1920/31694757568_7f03512946_c.jpg) (https://flic.kr/p/QhKVco)
(https://farm2.staticflickr.com/1921/45567295701_af57cedf89_c.jpg) (https://flic.kr/p/2cqCitk)
A centre was drilled in either end of the main part and the keeper.
(https://farm2.staticflickr.com/1964/44653264775_0b782e0f7b_c.jpg) (https://flic.kr/p/2b2RDVr)
A bit of milling to make room for temporary bolts.
(https://farm2.staticflickr.com/1931/31694669328_b8e9390049_c.jpg) (https://flic.kr/p/QhKsY1)
Then drill and ream both holes at the same setting.
(https://farm2.staticflickr.com/1924/45567276561_aa74b244a1_c.jpg) (https://flic.kr/p/2cqCcMk)
Mill away most of the waste to reduce the interrupted cutting in the lathe.
(https://farm2.staticflickr.com/1917/44653240075_c29144eeae_c.jpg) (https://flic.kr/p/2b2Rwzz)
To turn the radiussed sides to the big end I made a temporary centre with recesses to enable the bolts to function as driving dogs
(https://farm2.staticflickr.com/1933/44842290834_b6bc8de0f3_c.jpg) (https://flic.kr/p/2bjysMq)
It was a bit of a crude set up but fine for the few small cut to round the sides.
(https://farm2.staticflickr.com/1937/43749685200_0a4d388247_c.jpg) (https://flic.kr/p/29E1zcf)
A 12mm mandrel and a dab of Loctite 638 magic juice was used to hold the part for turning small raised rings.
(https://farm2.staticflickr.com/1925/30626055177_9349ac5570_c.jpg) (https://flic.kr/p/NEjxd6)
That takes me to this stage, it's a bit narrower than I would of liked but I'm concerned about clearences.
(https://farm2.staticflickr.com/1932/45516962422_dca75e5a0f_c.jpg) (https://flic.kr/p/2cmbk9b)
Time to turn the rod taper.
(https://farm2.staticflickr.com/1912/43749828600_2688fcc635_c.jpg) (https://flic.kr/p/29E2iPE)
So this is the part so far, with the keeper reduced in size and the taper cut the proportions look a bit better
(https://farm2.staticflickr.com/1969/45567423431_2af35c9c52_c.jpg) (https://flic.kr/p/2cqCXrz)
At this point I decided to leave the maching of the top until I'd split the bearing and had a trial fit to check clearences.
(https://farm2.staticflickr.com/1959/45567392061_992df6e923_c.jpg) (https://flic.kr/p/2cqCN7H)
(https://farm2.staticflickr.com/1954/31694817848_ac95d78cca_c.jpg) (https://flic.kr/p/QhLe7G)
Success, it fits and turns ok without fouling :D
(https://farm2.staticflickr.com/1923/30626253997_fcbe243246_c.jpg) (https://flic.kr/p/NEkyj2)
(https://farm2.staticflickr.com/1935/45567436861_22b61670ab_c.jpg) (https://flic.kr/p/2cqD2r8)
It's far from perfect but I reasonably happy and decided celebrate with a few pints of the dark stuff this evening. I'll finish it off and machine the crosshead over the weekend.
Hopefully in the next day or 2 I'll be in a position to see how well it turns with the parts so far operating together :pinkelephant:
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Well done Peter,
As with so many bits of engine they are rarely as difficult as we think they will be at the start :)
Jo
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Thanks Jo :)
I guess it's all experience, this is the 4th of these con rods I've made and each one is slightly better than the last.
I'm really looking forward to seeing how it turns over, it's a fairly mundane sort of engine but quite a bit more powerful than anything I've built so far so I can't wait to get it running on the hot stuff :D
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Hi Pete
That's starting to really take shape now, it looks a bit different to that random bit of scrap you bought at the last club auction ;D
Phil
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Cheers Phil :)
I'm quite pleased with how it's going, it will never be a thoroughbred Stuart but ought to be just as powerful. When you consider a full set of castings costs over £450 with postage and VAT but this will cost me about £70 then it has to be a bargain.
The club auction night is in a couple of weeks so I'll be on the look out for some more junk high quality merchandise. ;)
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Well I'm happy to say I have now fished the con rod and crosshead assemblies and had chance to see how the engine so far aligns and turns over, I did take photos and decided to make a short video. The first video wasn't right to I deleted it from my camera along with my photos :(
Anyway, things with the engine went fairly well and although I haven't yet made the crosshead pin or got a flywheel yet I have been able to see how it is shaping up.
I remade a second video so as there are no photos to show I thought I may as well show it :-
https://www.youtube.com/watch?v=OYfFRb9jkII
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The no4 is now starting to look like an engine with the flywheel now in place, firstly though I machined a couple of flanges to take the inlet and exhaust plumbing, I started out by turning 3 brass components as the 3rd will form the basis for the valve rod gland later.
(https://farm5.staticflickr.com/4908/31828979318_3297e86b1e_c.jpg) (https://flic.kr/p/QuBQDu)
A square of steel is then turned and threaded to become a mandrel to turn the parted of rear face and support the parts for later machining.
(https://farm5.staticflickr.com/4866/44976628744_a2a7626a66_c.jpg) (https://flic.kr/p/2bwqYLh)
It's not that easy to assess the radius of the mating surface of the casting so it's a bit of guesswork making trial cuts with the boring head in the mill until I seem to be getting the correct profile. Using the mill in reverse with the boring head is far from ideal but with a bit of common sense and light cuts it can achieve the desired result.
(https://farm2.staticflickr.com/1945/43883619930_5ae40d3f1d_c.jpg) (https://flic.kr/p/29RR2jJ)
Turning the block round to machine the other side it's starting to take shape
(https://farm5.staticflickr.com/4884/44787295865_9f1d5cd85d_c.jpg) (https://flic.kr/p/2beGAGi)
The likelihood is that I will machine away the raised boss on the casting as suggested in an earlier post but for now I've let it and I am machining the flange to match. It's slightly oversize here but still needs a bit of filing to round the ends.
(https://farm2.staticflickr.com/1938/43883580330_055290e0a8_c.jpg) (https://flic.kr/p/29RQPxY)
Quite happy with these.
(https://farm2.staticflickr.com/1929/43883558770_7122aa7321_c.jpg) (https://flic.kr/p/29RQH9f)
The square block serves as a holder for marking out then drilling.
(https://farm5.staticflickr.com/4906/44976532074_03ce1d4e54_c.jpg) (https://flic.kr/p/2bwqu2y)
(https://farm5.staticflickr.com/4830/44976714454_2df814b9b0_c.jpg) (https://flic.kr/p/2bwrqf3)
With the flanges made it's on to the flywheel. I opted for a 5 curved spoke casting as this style has the wider diameter hub I need.
(https://farm2.staticflickr.com/1932/44787614925_9e22c9fdba_c.jpg) (https://flic.kr/p/2beJexk)
I guess we all have different techniques for tuning flywheels but for the benefit of other novices this is how I do it. Firstly hold in the chuck by the outer edge then get the inner rim running as true as the casting allows.
(https://farm5.staticflickr.com/4831/44787593235_58c7bd86a5_c.jpg) (https://flic.kr/p/2beJ86n)
It's now possible to machine all the features on this side and part of the outer rim. Once happy with the turning I drill and ream for the 12mm shaft.
(https://farm5.staticflickr.com/4837/45701840351_aefb592580_c.jpg) (https://flic.kr/p/2cCvSUF)
A close fitting 12mm arbour is turned and the wheel is turned over then locked in place with 638 green snake venom. Provided the arbour is a good fit it should run true enough to turn the remaining features. I'm not a big fan of these cheapie brazed carbide tools but cutting left to right this one seems to work well.
(https://farm5.staticflickr.com/4907/44787529975_aeeef52940_c.jpg) (https://flic.kr/p/2beHNhF)
The arbor serves as a holding fixture to drill for a grub screw.
(https://farm5.staticflickr.com/4906/30760998727_11cd268e0f_c.jpg) (https://flic.kr/p/NSfae2)
That now takes me to this point.
(https://farm2.staticflickr.com/1914/30760921337_d97e7938d4_c.jpg) (https://flic.kr/p/NSeLdH)
(https://farm2.staticflickr.com/1921/44976778884_f68586a3c6_c.jpg) (https://flic.kr/p/2bwrKoU)
(https://farm5.staticflickr.com/4827/44787470595_31a8d61920_c.jpg) (https://flic.kr/p/2beHuCT)
Starting to take shape :)
https://www.youtube.com/watch?v=5DBwyGASjYc
Hopefully within a week or 2 I'll be able to get it running :-)
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Hello Peter,
Looking real good at this point. I was not able to view your video?
Have a great day,
Thomas
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Thanks Thomas :)
For some reason the video doesn't appear to have uploaded properly so I'm re doing it. It is only a 3min video explaining what I intend to do next etc but should be re posted shortly.
Edit - It should have uploaded now.
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Great progress Peter. Looking good...
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Thanks Gary, I now have the valve chest partly made so hopefully I'll have it running in a week or 2 :)
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I'd really like to get the small engine up to the same build stage as the 'biggun' but as I'm getting close to being able to test run the no4 I've decided to continue with it first. Although the valve chest isn't quite finished it's well on the way so here is an update of where I'm now up to.
The valve chest casting doesn't have a raised boss to drill for a valve rod guide and I guess it isn't really essential but I'd like the finished engine to have one so I've decided to make my own. I was under the impression that no4 and no9 cylinder / valve chest castings were the same but as my casting has the 'S' orientated for a horizontal (no9) engine this may explain the absence of the valve rod guide boss.
Anyway enough of that, first thing to do is to square of the chest casting in the mill.
(https://farm2.staticflickr.com/1928/45783313121_71d01a1e33_c.jpg) (https://flic.kr/p/2cKHrVB)
With the cover similarly squared off it's time to drill the 4BA fixing holes on both parts together. I kinda think an engine of this size could possibly benefit from more fastenings (maybe 10?) but the drawings show 6. so 6 it is. I'll mill out the 'S' later.
(https://farm5.staticflickr.com/4916/45733212202_b7f99d71f4_c.jpg) (https://flic.kr/p/2cFhEEE)
I hope this method will line up ok to drill into the cylinder casting :facepalm:
(https://farm5.staticflickr.com/4875/45783393111_e2e2e3390a_c.jpg) (https://flic.kr/p/2cKHRGK)
Well with them drilled I may as well tap them
(https://farm5.staticflickr.com/4842/44870322215_47e0e600fe_c.jpg) (https://flic.kr/p/2bn38x6)
Drilling for the inlet flange I made earlier.
(https://farm2.staticflickr.com/1972/30843469327_4666ae36e2_c.jpg) (https://flic.kr/p/NZwQRV)
The valve rod needs to enter the chest at 3/8ths from the port face which isn't quite central to the casting boss but the intention is to machine the brass flange and the casting as a single unit so the finished result should be central. It is drilled and reamed at 5mm with an 8mm dia milled hole 7mm deep to accept the packing gland.
(https://farm5.staticflickr.com/4887/44870299355_d02d89c0b0_c.jpg) (https://flic.kr/p/2bn31JX)
It wasn't practical with the tooling I have to drill right through the casting for the valve guide on the top face, so I drilled from above with a vice stop to hopefully pick up the same axis. It is then tapped at 1BA.
(https://farm2.staticflickr.com/1967/44870289635_cb9eb0f391_c.jpg) (https://flic.kr/p/2bn2XRn)
So with the 5mm valve rod in place I'm up to here.
(https://farm5.staticflickr.com/4814/43965967160_2311e2d650_c.jpg) (https://flic.kr/p/29Z85hy)
It lines up ok but is a bit tight although I think it should be fine. The top (free end) of the valve rod needs turning down to a smaller dia (prob 3mm) and it will then locate in a drilled guide. I'd like oil to be able to get past the valve rod in its guide so assuming the rod is 3mm dia I'll drill the guide at 3.1mm and this hopefully will ease the present tightness.
(https://farm5.staticflickr.com/4872/45058620924_79398c0cd7_c.jpg) (https://flic.kr/p/2bDFdby)
It seems to be taking shape.
(https://farm5.staticflickr.com/4855/31912002908_2dd2da61fb_c.jpg) (https://flic.kr/p/QBXmEG)
With a bit of luck I'll get the valve rod gland fitted and profiled, followed by the top guide and slide valve in the next day or 2. That should allow me to test how it responds to the valve before making the eccentric :)
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I'm pleased to say I now have the valve and valve rod in place and things seem to be coming along.
The valve rod is 5mm steel turn at one end to 3mm where it will enter the guide (I didn't photograph making the guide but it is a simple turning and drilling job on a piece of hex brass), another short portion is turned down to 4.7mm to thread at 2BA for the valve nut. I did wonder I'd need a steady whilst tuning but the deepest cuts are near the tailstock centre and the turning for the thread only involves 0.3 mm off the diameter so with very fine cuts things went well.
(https://farm5.staticflickr.com/4849/45765593472_8f03328507_c.jpg) (https://flic.kr/p/2cJ9Cuq)
I'd already done the preliminary work on the valve rod gland to it was now just a case of bolting it in place then using the boring head in the mill to profile it along with the casting boss. There were a few hollows in the casting and to fully machine them out would have meant making the part thinner than I wanted so I chose to stop here then finish with a file and emery.
(https://farm5.staticflickr.com/4883/43998399310_583165be38_c.jpg) (https://flic.kr/p/2a2Ziey)
The valve block is the usual slide valve and is machined from a piece of brass, it needs a 1/2" x 9/16" pocket on the underside so once machined to the overall size the pocket is marked out. (the small hole is just a remanant of a previous operation in the in the piece of scrap and is of no significance)
(https://farm5.staticflickr.com/4909/44902148555_726a02cf58_c.jpg) (https://flic.kr/p/2bpRfp6)
The smallest slot drill I have is 3/32" and that coped nicely at machining the pocket.
(https://farm5.staticflickr.com/4825/43998357750_9d3cd58737_c.jpg) (https://flic.kr/p/2a2Z5T1)
(https://farm5.staticflickr.com/4860/31944184568_55f1023503_c.jpg) (https://flic.kr/p/QENi9U)
To accommodate the valve nut and rod it's now just a matter of milling 5mm channels on the outer face
(https://farm5.staticflickr.com/4913/31944161998_f159a17bc1_c.jpg) (https://flic.kr/p/QENbrL)
That then takes me to this point, it's a bit boxy compared to the one in the Stuart plans but it will never be seen and I'm happy with the critical dimensions
(https://farm5.staticflickr.com/4849/30875138677_8a3abf02ec_c.jpg) (https://flic.kr/p/P3ka4c)
It fits ok an slides nicely so I think it will do the job. If need be I can always trim a bit off the outer profile to improve steam flow in the chest if it is too big to the point of choking the engine.
(https://farm5.staticflickr.com/4902/43998277470_d67398288c_c.jpg) (https://flic.kr/p/2a2YF1S)
Digressing slightly and thinking forward I thought as I intend this engine to run on steam it would probably be a good idea to fit drain cocks, forum member Florian saw me mention them and kindly offered to sell me a pair of his homemade drain cocks at a good price. I bought them and I'm well impressed with the quality, they ought to give a nice finishing touch to the engine once fitted :)
(https://farm5.staticflickr.com/4853/44902016355_2b5ba77fa8_c.jpg) (https://flic.kr/p/2bpQz6M)
(https://farm5.staticflickr.com/4813/43998223360_ce4a24b197_c.jpg) (https://flic.kr/p/2a2YoVW)
https://www.youtube.com/watch?v=PFVaMoOIhNs
Not long now until steaming up :)
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Thats quite a delicate bit of turning!
:popcorn: :popcorn: :popcorn:
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Thanks Chris, I found that with a newly sharpened HSS parting blade it worked quite well, I managed to get the open end to 3mm dia to fit in the brass guide drilled to 3.1mm that seems to give a bit of allowance to stop the rod binding in the guide and allow oil into blind end.
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Great progress Peter. Looking good!
Florian's drain cocks are little gems too.
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Thanks Gary, with a bit of luck it will be chuffing away shortly :)
My main computer finally packed up after about 6 years of hard labour so I did have a few days with only my tablet which isn't great for taking images, but now armed with my new sooper dooper Windows whateveritis computer I have now been able to upload a few images from my camera showing the progress so far.
Firstly I decided to fit the new drain cocks, the intention is to run this engine on the hot stuff so it made sense to fit drain cocks. With M5 fine threads I found that tapping into cast iron wasn't a great success so I opted for fitting threaded brass sleeves first.
(https://farm5.staticflickr.com/4855/46056759631_41386b3db8_c.jpg) (https://flic.kr/p/2daSW3B)
With the cylinder threaded they add a nice little touch and I'm pleased with the look. They may need a bit of shimming to get them both upright and parallel but I'll deal with that at the cladding stage.
(https://farm5.staticflickr.com/4834/46056214901_780ce72f94_c.jpg) (https://flic.kr/p/2daQ97H)
Making the eccentric seemed to be the obvious next step so it's time to turn down a piece of steel that will form the sheave. I did wonder about making this from brass and making a steel eccentric strap but settled on the opposite, so steel it is...
(https://farm5.staticflickr.com/4899/46056562851_cb4546228d_c.jpg) (https://flic.kr/p/2daRVxR)
Another area I pondered over was how to 'captivate' the strap on the eccentric, I thought it may be easier to cut a groove in the sheave and turn the strap with a raised internal diameter to match but having looked at other engines it seems it is more usual to have the groove in the strap and the raised 'ridge' in the sheave so I thought I'd give it a try.
Here I'm starting to turn the sheave diameter but leaving the 'ridge'. The plans call for this to be 1 /32" high which doesn't seem a lot to me but I'll stick with that.
(https://farm5.staticflickr.com/4873/46056261891_a2b09c643b_c.jpg) (https://flic.kr/p/2daQo5T)
With the outer diameter successfully turned I need to now work on the 5/32" throw so the crossslide is set at the required radius allowing the tool to scribe a line, a centre punch marks the spot :)
(https://farm5.staticflickr.com/4891/31117401287_b09c65c42e_c.jpg) (https://flic.kr/p/PpJPhK)
With the part now sitting on parallels in the 4 jaw its a simple job to line the punch mark up with a tailstock centre to obtain the required offset.
(https://farm5.staticflickr.com/4902/45332111414_ce04d149e2_c.jpg) (https://flic.kr/p/2c4QVnQ)
Drilling and reaming to 12mm for the crankshaft.
(https://farm5.staticflickr.com/4818/44240640300_860cab38b9_c.jpg) (https://flic.kr/p/2apoR3m)
I hadn't noticed until now but it looks suspiciously like I may have left a parallel in the chuck while turning the boss :facepalm: Anyway I got away with that one ;)
(https://farm5.staticflickr.com/4889/31117660197_d2beaf8f86_c.jpg) (https://flic.kr/p/PpL9fH)
Kinda looks like and eccentric sheave, so time to part it off.
(https://farm5.staticflickr.com/4845/46006497432_35303cb60c_c.jpg) (https://flic.kr/p/2d6rjQY)
Parting off with an offset workpiece probably isn't a good idea but with a sharp tool it works fine.
(https://farm5.staticflickr.com/4899/46056476611_e83642d46d_c.jpg) (https://flic.kr/p/2daRtUX)
So far so good...
(https://farm5.staticflickr.com/4808/31117623247_0831904fd3_c.jpg) (https://flic.kr/p/PpKXgD)
With the sheave tapped at 3mm for a grub screw it time to look at the eccentric strap. A disc of scrap brass about 9mm thick looks just about big enough for what I need, I'm not too worried about the outer profile being exactly as the Stuart drawing suggests as long as the finished item looks appropriate in scale, shape etc. Here it has been hacksawed in half then silver soldered back together for machining. A small flat on each side was milled to help holding in the 4 jaw and aid profiling later.
(https://farm5.staticflickr.com/4840/31117434367_38ee208026_c.jpg) (https://flic.kr/p/PpJZ86)
Before mounting the strap in the chuck for boring I thought it worthwhile making a tool to cut the internal groove and testing how it performed. Broken centre drills are a readily available item for most beginners and they make useful blanks when it comes to making one off tools.
This little fella is a bit rough and ready but ought to manage a small groove in a piece of brass.
(https://farm5.staticflickr.com/4858/31117609127_3faf8ca713_c.jpg) (https://flic.kr/p/PpKT5c)
(https://farm5.staticflickr.com/4894/32185165998_f9c04ddce5_c.jpg) (https://flic.kr/p/R36ox9)
With a simple holder made it seems to cut external grooves ok at the correct size for the eccentric.
(https://farm5.staticflickr.com/4817/46056393781_a6da4597d7_c.jpg) (https://flic.kr/p/2daR4hR)
The strap is drilled then bored to be a close fit on the main body of the sheave.
(https://farm5.staticflickr.com/4842/45144488545_90b95c8380_c.jpg) (https://flic.kr/p/2bMgiCM)
This photo isn't great but here I am ready to plunge in on the far side and (hopefully) end up with a neat groove. I chose to cut away from the camera with the lathe in reverse largely because it was easier to see what was happening but I guess it's not really important either way.
(https://farm5.staticflickr.com/4819/32185109208_a2aa30af56_c.jpg) (https://flic.kr/p/R366E1)
It seems to have done the job :) There is a hint of chatter on the bottom surface of the groove but it is small and that area shouldn't be a contact / running area.
(https://farm5.staticflickr.com/4855/46056354381_f9c542ab83_c.jpg) (https://flic.kr/p/2daQRzx)
Quite happy with that...
(https://farm5.staticflickr.com/4886/31117482257_65a68b8967_c.jpg) (https://flic.kr/p/PpKemM)
(https://farm5.staticflickr.com/4866/46006313262_1750a50413_c.jpg) (https://flic.kr/p/2d6qo6C)
I'm not yet sure how well the strap will fit until I've profiled it then split it to assemble over the sheave but I'm cautiously optimistic.
The next stage after finishing the eccentric assembly will be to make the rod leading to the valve rod, I could do with a bit of advice here if anyone can help. The eccentric sheave will sit outside the line of the valve rod, it's only small (perhaps 3mm) but does mean I'll have to incorporate a 'dogleg' in the eccentric rod :(
I had initially planned on the rod being a tapered flat bar but now that I need to add an offset I'm thinking a round rod about 5mm dia may be a better option. Anyone got any advice how to create accurate 'dog legs'? Will heating the steel help? I'd be grateful for any advice :)
With a bit of luck I'll have it running in a few days :pinkelephant:
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Looking good
Don't right off a flat rod just yet as they are easy to offset where they fix to the strap so you can keep a straight rod, just position the fork as needed
(https://img.photobucket.com/albums/v156/jasonballamy/Engineering/Cameron%20Steam%20Pump/IMAG3509_zpsbeef7d49.jpg)
If you do want to put a jog in the rod then a simple way is to stand two bits of 3mm flat vertically in your vice with a gap between equal to the length over which you want to form the jog. Then take your 5mm rod and put it horizontally in the vice with one bit of the flat steel in front and the other behind. Now tighten the vice to bend the metal. Next up from that is to make a jig, this was for a double bend but same sort of principal
(https://img.photobucket.com/albums/v156/jasonballamy/Engineering/Lecky/DSC03357_zpsxxfcs1ff.jpg)
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Thanks Jason,
A flat bar with a taper does look neater and a bit more like the real thing so I'll take a few measurements tomorrow and assess what is achievable. I sort of wanted to keep open the option to add a Stephensons reversing gear later depending on how well the engine looks and performs. Having made all of the moving parts from barstock if I do add reversing gear I'd want to do likewise if I can.
The eccentric offset is a bit annoying but not the end of the world, when I made the soleplate and bearings I kinda made them up as I was going along so a bit of a cosmetic error has crept in. Ultimately it stems from making the crankshaft larger than the plans and then the same with the 'Lego' bearings.I've made some roughed out bearing caps here to get things secured down but they are still work in progress :headscratch: A bit of rounding off and some brass oil cups ought to soften things a bit.
This the lie of the land at the moment with the sheave against the bearings :-
(https://farm5.staticflickr.com/4860/46058329851_a6ca1b32dc_c.jpg) (https://flic.kr/p/2db1YPn)
(https://farm5.staticflickr.com/4816/44242385170_83716af71c_c.jpg) (https://flic.kr/p/2apxMJj)
Cheers :)
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You could easily half the thickness of the flange on that bearing which will pull things back a bit.
Flat also works for reversing gear, here most of the offset is done with the forked ends, the pump rod is jogged. Both use the same simple lap joint to fix rod to strap
(https://img.photobucket.com/albums/v156/jasonballamy/Engineering/Minnie4.jpg)
Or you can get a bit more adventurous and bolt the rod to the end of the strap, one rod is bent and the forks differ
(https://img.photobucket.com/albums/v156/jasonballamy/Fowler%20A7/PICT0103.jpg)
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Thanks :)
Now you have mentioned it and I've had a proper look, I agree the bearing flanges can be reduced significantly and with a bit of luck if I machine a flat rod properly I ought to be able to accommodate the offset (watch this space ;) ).
In the top photo of reply 220, is that a split strap running on a sheave over its entire width with side walls instead of a guide groove?
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On the Minnie which is the top engine all the eccentrics have a 1/32" flange either side so the strap just has a plain bore right through.
The lower photo has them done like yours with the raised rib in the middle of the eccentric.
In both cases the strap was bored after splitting.
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Great progress Peter. Interesting process. Not long now till it's running...
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I've now pretty much finished the eccentric strap so that only leaves the eccentric rod to make before being able to carry out a trial run :)
Profiling the outer edge of the strap will involve the dreaded turny table so I decided to make a clamping fixture first
(https://farm5.staticflickr.com/4856/44289770790_80715b7a30_c.jpg) (https://flic.kr/p/2atJDPL)
With a close fitting spigot and a M6 threaded hole to allow for securing the part I'm hoping this will do the job.
(https://farm5.staticflickr.com/4813/44289970980_10cd81e71a_c.jpg) (https://flic.kr/p/2atKFkj)
Holes are drilled at 5BA clearance.
(https://farm5.staticflickr.com/4889/45194634075_231bb20cd6_c.jpg) (https://flic.kr/p/2bRGj9T)
A bit of milling reduces the amount of waste to remove later.
(https://farm5.staticflickr.com/4875/46056203262_3e0be16720_c.jpg) (https://flic.kr/p/2daQ5E3)
Centring on the table with a co-ax indicator
(https://farm5.staticflickr.com/4828/46056121332_79c938d2b8_c.jpg) (https://flic.kr/p/2daPEis)
Although only an M6 bolt holds the part down it is prevented from moving by the spigot so it is more secure than it looks and I'm only making small cuts with a 4mm mill.
(https://farm5.staticflickr.com/4842/46056105192_572ef734d6_c.jpg) (https://flic.kr/p/2daPzvb)
The lower half is taking shape
(https://farm5.staticflickr.com/4864/31166740527_a207f36974_c.jpg) (https://flic.kr/p/Pu6G8i)
Hmmm, it's not perfect - I somehow managed to round the top half at a slightly larger radius but it isn't a complete disaster.
(https://farm5.staticflickr.com/4878/46056078892_cd38b22c39_c.jpg) (https://flic.kr/p/2daPrFJ)
(https://farm5.staticflickr.com/4918/46056063222_d8c126d66a_c.jpg) (https://flic.kr/p/2daPn2y)
Fortunately it fits over the sheave nicely but I think a bit of running in may be needed. In the following photos it will close up tightly but is difficult to turn so I've got the temporary fixing a bit loose. My hope is that after a while I'll be able to close up the gap fully.
(https://farm5.staticflickr.com/4907/46056054752_770974443e_c.jpg) (https://flic.kr/p/2daPjvw)
(https://farm5.staticflickr.com/4847/32234715348_21cd968371_c.jpg) (https://flic.kr/p/R7tkQh)
So that largely finishes the eccentric assembly, its never going to win any awards but on the positive side it does operate smoothly without sloppiness so I'm reasonably satisfied :)
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Nicely done!
If your rotary table has a hole in the center, you can turn a shoulder on the back of holders like that to match the size of the hole and make it self centering.
:popcorn:
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Just catching up on this thread Peter. Lovely work and hope to see it running soon. :ThumbsUp:
Bill
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Thanks for the support guys, it's good to know people are still following along :)
I'm hoping I'll have it chuffing away in a video tomorrow :pinkelephant:
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Only a few photos to but I'm pleased to say I'm now in a position start running the no4 and work towards gaskets, painting, cladding etc.
I had expected to need to add a 'dog leg' in the eccentric rod to achieve alignment with the valve rod but after following earlier advice on making a flat rod with a forked top it became unnecessary (cheers Jason :) )
Here I am cutting a small recess and drilling for 7BA clearance in the eccentric strap.
(https://farm5.staticflickr.com/4906/32259368778_7ba21b4c1c_c.jpg) (https://flic.kr/p/R9DGrq)
I added a round bearing ring to the valve rod then set about machining the eccentric rod to fit
(https://farm5.staticflickr.com/4819/32259418988_8cb80906ff_c.jpg) (https://flic.kr/p/R9DXn7)
The overall shape is largely done here with one side of the fork left to mill down to size.
(https://farm5.staticflickr.com/4858/46080496462_e74557f7f2_c.jpg) (https://flic.kr/p/2dcYAbj)
Although not quite finished in this photo I couldn't resist installing it first to see how things fit together and operate. It needs the top rounding and perhaps a small taper to soften up the appearence a bit but it does operate smoothly.
(https://farm5.staticflickr.com/4882/32260710798_b9d9bf7b42_c.jpg) (https://flic.kr/p/R9LznG)
Well, with all the moving parts in situ it seems a shame not give it a try :)………
https://www.youtube.com/watch?v=-XAH6_GCdJU
Next job will be to make a boxbed base and an outrigger bearing to support a small pulley.
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very Nice :)
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Thanks Jason, I'm quite pleased with it :)
I may put the flywheel back in the lathe for a quick spin, at the moment the inner rim casting edge makes it look as though the whole thing has a wobble but the machined surfaces are running true.
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Nice one Peter :ThumbsUp:
Phil
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Thanks Phil,
I may get it running on the hot stuff today :)
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With gaskets and packing added I couldn't resist cooking some water :)
https://www.youtube.com/watch?v=cFsKG-3geHE
Since reassembly it appears to have developed a bit of a knock at BDC, I think the piston rod just needs a turn on the screw thread adjustment so it shouldn't be a problem to rectify.
Next job is to make a pulley and outrigger bearing then mount it on the cast iron slab, it will make a great doorstop if nothing else ;)
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Not much wrong with that and the little 3" boiler seems to keep up quite well unless you rev it fast.
Have you tried loading up the flywheel with your hand to see what potential it has to drive things, should also give a bit more of a bark when it's under load.
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Thanks Jason, with about 60psi I dont think I could stop the flywheel, it would certainly take some effort if I could, depending what use I put the engine to it will run at perhaps 1000+ rpm so with reduction belt drive it ought to deliver usable torque.
I'd expect the power output to be higher once I have a bigger boiler that is capable of delivering more steam to cope with engine loading.
I have a few old motors laid around so I've just bought a cheapo multimeter with a view to seeing if I can make myself a bit of electricity using the engine.
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Great job and really looks nice under steam.
Have a great day,
Thomas
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Nice! :ThumbsUp:
You've got to be feeling pretty good!
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Another great project - love the steam !
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That is quite cool seeing it run under steam! :ThumbsUp:
Well done!
Kim
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nice to see it running.
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Hi,
Great to see a steam engine running on steam, beautiful engine, congratulations !
if you plane to use her mainly on shows or demo, it is convenient to have a shortened admission period, although it involves major change in the engine, as Stuart engine have about 85% cut off, which is very demanding for a small boiler !
But obviously with a larger boiler this impressive steam plan would be more spectacular !
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Thanks guys.
Although I can't really do much about the admission period I may need to adjust the timing, when I assembled it for the demo I just set the eccentric sheave at 900 and it ran well so I didn't alter it. A bit of fine adjustment may help a bit.
I'll update the build log once I have made the base and will make a proper video once some proper pipework has been added :)
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Very nice engine, Peter.
Congratulations!
You are steadily becoming a master of your craft.
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Very nice! I love being able to see it run on steam.
Dave
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Well done Peter. Good to see it running on steam.
Now for some tidy piping, a lubricator and exhaust separator. I suspect it will run even better when you set that valve rod and eccentric position set more accurately.
Looking forward to seeing the other one up to this stage as well.
MJM460
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The larger of my 2 engines still isn't finished :-[ but it has had a lick of paint and pipework is bought ready for plumbing it properly so I decided to give it a test run on the hot stuff.
Once it fully completed I'll show the finished result :)
(https://live.staticflickr.com/31337/32623475447_4fc2bbff88_z.jpg) (https://flic.kr/p/RGPQEB)No4 engine on coal. (https://flic.kr/p/RGPQEB) by Peter Nichols (https://www.flickr.com/photos/96977152@N04/), on Flickr
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Hello Peter,
Great to see all the action and steam going on at one time.
Have a great day,
Thomas
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Thanks, just need to get round to plumbing it and increasing the diameter of the exhaust to the boiler now.