Author Topic: Arnold's take on the MEM Corliss  (Read 167308 times)

Offline arnoldb

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Re: Arnold's take on the MEM Corliss
« Reply #465 on: June 29, 2014, 07:42:03 PM »
Vince, Jo & Baron, thanks for checking in  :)

The backstop was a real quickie - but I have a hunch I'll be using it a lot.  Not nearly as nice as Don's!

Bronze for the feet  :o That is rather expensive stuff to be using for feet, it looks like a purchased bit as well  :disappointed: .
Yes - purchased phosphor bronze...  Funnily enough, that's quite a bit cheaper and more obtainable  here in Windhoek than brass - and about the same price as stainless steel and cast iron.  Apparently the mining industry here in Namibia uses quite a lot of the stuff, so i think that's why it's "reasonable" here.
I could have used aluminium, but seeing as there's not a single bit of that on the rest of the engine, I went the more expensive route.  Could possibly have made them from wood as well, but there's a couple of things I want to get in place before doing too much wood-work in the shop...

It seems everyone building these "MEM Corliss" engines are going about it fairly slowly...  For me, work, a trip to South Africa for a course and exam, and a bout of flu last weekend has kept me out of the shop.  I managed to steal a couple of hours today though, and made a start on a regulator valve.  That's not on the plans, but I want it to add some more interest to the engine and "break the blue" a bit more.

Most of the shop time went on doing a bit of research into valves, digging around the stock pile to see what I had available, and coming up with a plan.  For the most part, it's based on George Britnell's valve design, but I'm adapting the sizes and threads to suit what I have available.

I free-hand turned some 16mm brass - I didn't think it would be much use for me to make up a form tool for this job, as I'm unlikely to make many valves of this size in future:


After some work with a file to blend in the curves, followed by emery to smooth  things, it was off to the mill and dividing head for the hexagonal heads:


That was followed with a cross-drilled 4mm  hole with a 7mm counter-bore for soldering in the connector pipe later:


After parting it off the parent stock, my shop time was up  :'( - so this is what's left for today's effort:


Kind regards, Arnold
Building an engine takes Patience, Planning, Preparation and Machining.
Procrastination is nearly the same, but it precludes machining.
Thus, an engine will only be built once the procrastination stops and the machining begins!

Offline BaronJ

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Re: Arnold's take on the MEM Corliss
« Reply #466 on: June 29, 2014, 08:03:13 PM »
Hi Arnold,

I like that valve body.  The curves look very good.  I know you said you did it freehand !  Until I realised you meant manipulating the cross slide I thought that you had used graving to do it.  Either way, it's nice.
 
Best Regards:  Baron.

I don’t regret the things I’ve done, I regret the things I didn’t do when I had the chance.

Offline vcutajar

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Re: Arnold's take on the MEM Corliss
« Reply #467 on: June 29, 2014, 10:08:12 PM »
Quote
are going about it fairly slowly...

I love that Arnold. That must be the understatement of the year. :Jester:

Where are you going to put that valve?  On top of the cylinder block?

Vince

Offline Don1966

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Re: Arnold's take on the MEM Corliss
« Reply #468 on: June 30, 2014, 12:02:10 AM »
Gee Arnold, somehow I missed the post about the feet. I love them and a nice addition to an already beautiful setup. The valve came out great also.  I love it when I can do some graving.

Don

Offline arnoldb

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Re: Arnold's take on the MEM Corliss
« Reply #469 on: July 06, 2014, 07:21:55 PM »
Thanks Baron, Vince & Don

Yes - just free-style using the cross-slide and carriage...  Graving and spinning are two lathe disciplines I still want to get around to!

Vince, yes - the valve will go on top of the block.  I'm not sure how it will look though; I hope it comes out OK.

I managed to grab a couple hours shop time over the weekend.  First off was to finish the valve body - it needed some threading done on the other end.  To mount it, I used an M6 cap screw shoved through the rear of the ER collet - not very accurate, but good enough for this job:


The valve body was then screwed onto that and tight up against the collet face, and the other end opened about 4mm deep to 5mm diameter and tapped M6 for the incoming air line fitting:


Next up the valve spindle.  A bit of 6mm stainless steel rod was chucked up in the collet chuck with about 10mm extending from the chuck, and the end turned down to 3mm and threaded M3 with a tailstock die holder.  Then I extended the workpiece further out and turned an 18mm long section down to 4mm:


After extending the workpiece further out again, I threaded a short section M6 - once again with a tailstock die holder:


I forgot to take a photo of the next step...  I used a V-shaped tool to turn off a section of the threads close to the lathe headstock, and finally, with the top slide set over to 30o "parted" the workpiece off using the V tool.  A later photo shows the result.

Next up it was the double-ended adapter that keeps the spindle in place and help form the spindle packing.  I started that from some 10mm hex brass and (stupidly) formed most of it in one go and drilled the hole for the valve spindle:


That was parted off, the brass in the chuck faced nicely and drilled and tapped M6 to fit the threaded end of the workpiece.  the workpiece was then screwed into that so that I could thread the other end for the pack nut.  Easy, no?...
While threading the other end, things got a bit stiff - and not listening to Mr. Gut Instinct who told me to stop, I gave it another turn.  Just to show that things do go wrong, here's the result:

Fortunately, it was easy to remove the broken bit from the die nut - the hex helped a lot.

I called it a day for Saturday at that point - there was a cold front moving in and the shop became unbearable.
The collection of parts for the valve stood at this (including the broken bit):


This will give an idea how things go together:


Made it back to the shop this afternoon... 

I've always struggled with silver soldering -  mostly because I'm inclined to use too much flux and solder, and the solder ends up going everywhere.  Today I spent some time carefully assembling the bits with just a little flux, and with a minimum application of silver solder, soldered the lot together:

That came out surprisingly well - even though it does not look like it.

That lot went into the pickle - I accidentally dropped it in from too far up and splashed some pickle out.  Fortunately that's no biggy, as I use citric acid for pickling (this batch is well-used already - hence the colour):


While waiting for the pickle to do it's thing, I started on the valve handwheel from a bit of bronze:


Off to the mill and rotary table, and it was a quick job to drill some holes in it:


That was then taken back to the lathe, center drilled and threaded M3 to match the valve spindle, and parted off.  It's an "interesting" experience taking a parting cut through cross-drilled holes  :LittleDevil: .  To finish the parted side, I used the small lathe, as it's 3-jaw chuck with outside jaws were convenient for this step:


That left me with a functional handwheel:


The pack nut was also made from some 8mm hex brass, as well as the bit I stuffed up yesterday - those are visible next to the valve spindle in the above photo. 
The valve body came out of the pickle, and I did something I rarely do - gave myself a pat on the back - as the result is the best darn silver-soldering job I've ever done  :whoohoo: :


I spent some time cleaning the bits up and took a family photo:


Then assembled the valve:

I'm rather pleased with that...

A shot of where it goes on the engine:


I'm struggling to find some suitable piping to make the final connections.  Everything I have in stock is either too thick or too thin.  The only supplier who has some suitable piping in stock had a computer outage when I was there and couldn't even give me a price; I'll try and get back there this week to see if they are back to business...
The final piping is needed, as I still have to drill a hole in the base for that and finish mounting the base feet.  I'd like to do that in one session though, as the base has it's final finish on it and I'm not keen on re-doing bits of that.
Then it's on to final assembly - finally!

Kind regards, Arnold
Building an engine takes Patience, Planning, Preparation and Machining.
Procrastination is nearly the same, but it precludes machining.
Thus, an engine will only be built once the procrastination stops and the machining begins!

Offline BaronJ

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Re: Arnold's take on the MEM Corliss
« Reply #470 on: July 06, 2014, 08:06:47 PM »
Hi Arnold,


That valve has turned into a beautiful piece.  :cartwheel: :cartwheel: :cartwheel:   You should be justifiably pleased with it.  I know I would be.  :)

As far as soldering goes, I don't do much with silver braze.  I tend to used soft 60/40 and a hot air gun for small stuff.  One of the things that I'm playing about with is a speed controller for use with a 12 volt windscreen wiper motor.  I solder the power fet directly to the heatsink using the hot air gun.
Best Regards:  Baron.

I don’t regret the things I’ve done, I regret the things I didn’t do when I had the chance.

Online Kim

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Re: Arnold's take on the MEM Corliss
« Reply #471 on: July 07, 2014, 06:28:44 AM »
That solder job looks great, Arnold!  Your valve turned out beautifully!
I'll give you a hearty pat on the back for that one too!   :ThumbsUp:
Kim

Offline ths

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Re: Arnold's take on the MEM Corliss
« Reply #472 on: July 07, 2014, 01:23:30 PM »
Love the valve, as I do the rest of it. Hugh.

Offline arnoldb

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Re: Arnold's take on the MEM Corliss
« Reply #473 on: July 13, 2014, 06:12:16 PM »
Thanks Baron, Kim & Hugh :)

Baron, I'd have used the electronics solder too, but didn't want to have the "grey" lines from that showing...  Ahhh - heat gun...  As a young lad I used to find old computer boards and desolder ICs from them in bunches - back then it was mostly 74-series TTL chips.  Never used it to solder circuits together though; it heats up the ICs and other components above specifications, so they're likely to be damaged.

I didn't get a chance through the week to get the piping, so thought I won't get around to much this weekend.  A neighbour popped in Saturday morning looking for an odd water pipe fitting (I'm known for hoarding all kinds of crap potentially useful items...  While digging through the boxes of pipe fittings, I came across an old geyser thermostat - with a length of just the right size brass tubing on it:


Right...  measured it up, and it was just over 5.5 mm OD - doesn't make sense in metric, but that rang a bell and turns out to be 7/32" in imperial.  This is thin-wall hard brass tubing, so bending it would be well nigh impossible.  That would require making some pipe fittings.

First up, a 90o elbow fitting was needed.
I turned up a brass "tube" from some 7mm stock, about 20mm long and drilled 5.6mm through for a relatively loose fit onto the tube:


To make the elbow, that bit of tube had to be cut through at 45o - but holding it without squashing it would be a problem.  So  I turned another section of 7mm brass down to a close fit on the inside:


The tube and "arbor" was then clamped up at 45o in the mill vise with a bit of cardstock positioned so that it would squash the tube onto the arbor and keep both secure:


I used a 1mm slitting saw to cut it - but before starting I thought things through carefully.  This wasn't exactly a very secure setup, and one concern was that the end of the arbor would be slit off - before the main workpiece was slit through.  So I had to keep a careful look-out for that and stop things the moment the arbor tip was slit off and remove that.  If left in the "tube" it could rotate, catch on the saw teeth and jam up or rip things apart.  So I started cutting, and as I approached that point, I slowed the feed down and kept a hand on the stop switch.  The moment the bit of arbor started to wiggle, I stopped the machine:


Then I used the hooked end of a scribe to pull the bit out:


After which I finished the cut:

The little "nub" left on the separated part was easy to file off afterwards with a fine file.

On to another brass fitting - one end of a bit of 10mm hex was turned down to 6mm and threaded M6 to fit the valve, and parted off about 15mm long.  Then it was screwed into an M6-tapped bit of brass held in the chuck, turned down to 7mm OD for a bit to match the "elbow-in-making", drilled 5.6mm to about 5mm deep to fit the tubing, and finally drilled through 4mm:


A short section of the brass pipe was cut off, and inserted and I checked the fittings together with the valve:


The section of pipe was still a bit long, so I shortened that by another 8mm.  After a final check, I made tiny scratches on the under-side of the screw fitting - to be out of sight, but give an indication of where the direction of the elbow must go.  To help keep things together for soldering, I flared the end sections of the piece of pipe slightly.  This was easily done by just squeezing a long-nosed pair of pliers into each end; the taper on the pliers deformed the ends just enough to make things tight, but leave room for flux and solder to wick through.  I silver-soldered the bits together - once again using a minimum of flux and silver solder.
Then I set up to solder the rest of the elbow and down-pipe on:



To measure where to drill the hole through the base, I moved the engine block to the side of the base, and took measurements from the mounting-hole locations:


After some more clean-up it looked OK and I left off there for Saturday:


Today I carried on with more bits of plumbing - the down-pipe was cut to length, and a ferrule and M6x0.5 threaded fitting turned up.  The ferrule will just be used to tidy up the hole in the base, as that needs to be slightly larger than the pipe to fit the 6mm threaded section through:


I used soft solder to solder the threaded fitting to the pipe - after first sliding the ferrule on to the pipe:

Soft solder's fine here; nobody will see the fitting.

Something not often seen... Tapping wood.  That's M8 to fit the ferrule:

This teak is darn hard, and felt like tapping brass - just easier.

What it looks like in position on the engine:


I spent some quality time starting to add finished bits to the engine block, as well as finally properly fitting the feet to the base:


Week evenings are a loss trying to get anything done; even if I do have a gap, it's too cold in the shop.  And I doubt I'll be able to do much next weekend; I'm booked for some major after-hours work at a client...

Kind regards, Arnold
Building an engine takes Patience, Planning, Preparation and Machining.
Procrastination is nearly the same, but it precludes machining.
Thus, an engine will only be built once the procrastination stops and the machining begins!

Offline spuddevans

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Re: Arnold's take on the MEM Corliss
« Reply #474 on: July 13, 2014, 06:55:52 PM »
That is looking very fine :ThumbsUp: Arnold, and I like the way you fabricated the 90deg bend.

Tim
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Offline ths

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Re: Arnold's take on the MEM Corliss
« Reply #475 on: July 14, 2014, 09:46:17 AM »
Very nice soldering on the elbow, it can be risky silver soldering brass that thin. I'm always wary of the 'oops' moment when the brass flows better than the solder! Hugh.

Offline BaronJ

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Re: Arnold's take on the MEM Corliss
« Reply #476 on: July 14, 2014, 08:42:05 PM »
Very very nice Arnold.  That is coming along a treat.

I agree with your comments about threading teak.  Its tough stuff !  The coffee table had a loose leg, one of those steel pressed in nuts with two spikes that stop it rotating.  So I turned the flats off an M8 nut.  I screwed it onto a M8 bolt and cut the outside M12.  Then I used a bottom tap to thread the hole in the leg M12.  I had to use a lock nut and a spanner to get the nut to screw into the wood.  It won't come loose again.
Best Regards:  Baron.

I don’t regret the things I’ve done, I regret the things I didn’t do when I had the chance.

Offline arnoldb

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Re: Arnold's take on the MEM Corliss
« Reply #477 on: July 30, 2014, 08:16:48 PM »
Thanks Tim, Hugh & Baron

Hugh, I used some of my lower temperature silver solder for that; it's still some of the "nasty" type with cadmium in it, but it flows at a lower temperature than the others I have.  To flow, it needs nowhere near brass's melting temperature; when the brass just starts to glow red, it works fine, and I used a normal plumber's torch to solder that.

Like mentioned in my last post, I haven't gotten around to much shop time of late - been busy with my day job basically day and night.  This past weekend was the coldest so far this year in our Winter, and I didn't go to the workshop either - stayed indoors and did trivial things, and slept a lot to catch up to lost sleep.  I'm on leave this week, and had been attending to other matters that got neglected in the last couple of months, but this morning I finally got back to the shop.

The engine was finally properly mounted to the base, and I made up another (crude) connector to fit the intake piping from the bottom:


I masked the blue paint on the flywheel, thoroughly cleaned the rim, and gave that a coating of clear lacquer - that should stop it rusting in future.

Then I started assembling the engine - giving each part a final finish as I assembled it.  A couple more studs were made to fit the valve to the top valve passage cover.  I'd never made a proper bolt for the valve rod pivot, so that was made, as well as a couple of spacers (not on the plans) for the crankshaft.  The one spacer fits between the main bearing support and the crank web, and the other between the eccentric and the main bearing support.  I took the length measurements for these spacers directly from the engine - and they will retain the crankshaft in the correct place:

 :facepalm2: I didn't take a photo of where the spacers are fitted - I'll do that later on.

I thought I was done making parts with the above lot, but during further assembly, I found I don't have enough of the turned-down 3mm washers I used for the rest of the engine to fit the outboard cylinder cover, and I need a final pipe fitting and a retainer for it.  Unfortunately, shop time came to a close; the doggies wanted their dinner, Shrek the parrot very loudly and repeatedly proclaimed from the living room "Ek wil 'n kasie he!" - meaning he wants a bit of cheese, and "Ek wil pappa toe kom" - meaning he want's to come to "daddy".
So I left the engine assembled as-is to attend to the zoo creatures.  All the preliminary timing is set on the engine; it now just needs the outboard cylinder cover fitted, a final air connection, and, after some valve adjustment the blind valve covers on the opposite side of the block.  I left it at this:


 :whoohoo: - tomorrow should be a great day in the shop  ;D

Kind regards, Arnold
Building an engine takes Patience, Planning, Preparation and Machining.
Procrastination is nearly the same, but it precludes machining.
Thus, an engine will only be built once the procrastination stops and the machining begins!

Offline Roger B

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Re: Arnold's take on the MEM Corliss
« Reply #478 on: July 30, 2014, 08:32:50 PM »
Looking great  :praise2:  :praise2: Still following along  :ThumbsUp:  :ThumbsUp:
Best regards

Roger

Offline b.lindsey

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Re: Arnold's take on the MEM Corliss
« Reply #479 on: July 30, 2014, 11:27:35 PM »
Beautiful work on all counts Arnold. Love the feet, valve and just the WHOLE thing. Quite a showpiece you are making there!!

Bill

 

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