Author Topic: Arnold's take on the MEM Corliss  (Read 134670 times)

Offline tel

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Re: Arnold's take on the MEM Corliss
« Reply #45 on: February 10, 2013, 12:11:18 AM »
Quote
I rather make things from bits and stick them together if possible.  The crosshead guide is a candidate for this.  At  81mm long, with a 3mm thick 48mm diameter flange on one end and the rest of the length turned down to 27mm; rather than taking a bit of 50mm diameter x 100mm long round bar (the extra length is for chucking allowance) and turning it down to the sizes needed, I'll just make the crosshead from two assemblies - a bit of "pipe" from some 32mm hot-rolled steel I have, and the flange from some plate stock silver-soldered to it.

I did mine exactly the same way. only with cast iron and Loctite. Glued the oversized flange on and finish turned it after the Loctite had cured.

The older I get, the better I was.
Lacerta es reptiles quisnam mos non exsisto accuso nusquam

Offline Don1966

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Re: Arnold's take on the MEM Corliss
« Reply #46 on: February 10, 2013, 01:51:12 AM »
Glad to see more updates Arnold, she sure is shaping up. Waiting for you next update.

Don

Offline NickG

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Arnold's take on the MEM Corliss
« Reply #47 on: February 10, 2013, 10:19:51 AM »
Looking pretty but purposeful! Nice work.

Offline arnoldb

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Re: Arnold's take on the MEM Corliss
« Reply #48 on: February 16, 2013, 07:55:29 PM »
Thanks All  :praise2:

Carl, the tap was bound to break at some point - it's gone through at least a hundred holes, so I won't complain, especially since it was easy to get out of the hole  ;)

Like Bob mentioned, it's giving an idea what's needed for tooling...  I wish I'd made that boring bar earlier; it would have been much easier to do the cylinder with it as well...

I had a bit of a hectic week; I've been assigned to a large project that requires a lot of investigation and report writing at work.  I'm enjoying the project, but had to put in some extra hours in the evenings to make some deadlines.  On Monday evening my report-writing got interrupted pleasantly by my neighbour calling me over the wall.  He promptly handed me these:

Two of the smallest sized 400kPa (58psi) pressure gauges they sell.  Just about perfect for adding to small 40psi boilers  :whoohoo:

On to the project at hand.
I parted off the "tube" for the cross-head, on purpose making it 1mm shorter.  Then it was clamped up in the mill - I clamped it length-wise in the vise, as I didn't want to distort the bore - there was some fairly heavy-handed machining coming up, and I wanted it secure.  If it was clamped across in the vise, milling out the pockets would weaken it quite rapidly and it would easily distort or come out of the vise.  Just my thoughts - not necessarily correct though.  Then I located it's center, and drilled two 6mm holes through it:

The holes were then enlarged to 13mm.

A 14mm mill worked well to mill out the slots - I just poked it through one of the 13mm pre-drilled holes in the top, milled along to the next hole, and then finished with 0.5mm side-cuts along the length to get the slot to 15mm width.  The slot width isn't too critical; I could have left it at 14mm, or even taken it up to 16mm (I don't have a 15mm mill, but I do have a couple of 16mm ones).  Once the top slot was done, I repeated the process for the bottom one.  I nearly trashed the end mill though... while cranking it down to start in the hole, I forgot that the inside curve in the "pipe" would mean that the cutting flutes would contact the workpiece before it was close to the hole.  Fortunatley the cutter handled it well, and just took some big chips out very quickly without breaking.


After a bit of de-burring with a small half-round file, the bit was done:


I thought I had a bit of 50mm steel rod in stock to make the "flange" for the cross-head guide from   :noidea: .  Nope; it's only 40mm and way too small. It needs to be 3mm thick - so I had a look around for plate -  :ShakeHead: .  I have lots of 10x60mm steel flat bar.  Cruddy stuff to machine, but it will have to do - so I hatched a machining plan and cut a block of it.  As so often happens (for me at least), the choice was machine it on the mill or on the lathe. 
Well, I'd already had a mill session, so on to the lathe.  I used an old bearing outer shell as a parallel, and after crudely centering the workpiece in the 4-jaw chuck with eyeball MK1, tied the bearing shell down to two adjoining chuck jaws with a piece of binding wire:

Carl - and maybe others - like a bit of explanation...  The bearing shell would remain in the chuck while machining.  By tapping on the workpiece while chucking it up, the shell can be made to sit tight between the workpiece and chuck body, but I don't fully trust this.  My lathe's 4-jaw chuck is at least a year older than I am and still in pretty good nick, so I don't want that shell coming loose while turning and rattling around in there and possibly marring the chuck.  By tying it down to just two adjacent chuck jaws, its possible to loosen the other two chuck jaws to flip the workpiece around without having to redo the binding.  Cable ties works just as well for this, but I'm out of stock...
Note that there was no possibility for the "parallel" to escape between the chuck jaws.  NEVER EVER leave parallels in a chuck if there's any possibility that they can escape while working.

After facing the mill scale off one side of the workpiece, it was flipped around in the chuck, and then faced down to 3mm thick:


Some drilling and boring later, there was a hole in the middle to match up with the "pipe" section done earlier.  There's an "inside" flange left at the back that is 1mm thick.  This is also the reason why I made the pipe section 1mm shorter.  The pipe section must fit very square to this bit, and the inside flange will help with that.  The pipe bit is a light push fit into the hole, and I also added a bit of chamfer to the hole.  This is for space for solder to wick into to make the final joint a bit stronger


Here's how things fit together at the end of my shop session:

The pipe bit fits snugly in place, and the chamfer ring is clearly visible.  Earlier I mentioned that I'll silver solder these together, but I'm going to go with electronics solder.  It should be more than strong enough in this application, and there will be less cleanup involved.

Horror of horrors...  I've got measles:

NOT.  A stream of blue-hot chips splashed over me when I started - slightly over-vigorously - on facing off that square block on the lathe.  I guess it's the hobby-engineer's equivalent of lactic acid  :LittleDevil:

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 Jo

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Re: Arnold's take on the MEM Corliss
« Reply #49 on: February 16, 2013, 08:04:28 PM »
Thanks All  :praise2:

Carl, the tap was bound to break at some point - it's gone through at least a hundred holes, so I won't complain, especially since it was easy to get out of the hole  ;)

 :o I have a 12BA tap that I cut many more thread with, in steel. ;)

 :headscratch: I still don't understand what the binding wire was for :shrug:

Jo
Usus est optimum magister

Offline tel

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Re: Arnold's take on the MEM Corliss
« Reply #50 on: February 16, 2013, 08:08:25 PM »
Quote
I still don't understand what the binding wire was for

To stop the packing piece slapping around.
The older I get, the better I was.
Lacerta es reptiles quisnam mos non exsisto accuso nusquam

Offline zeeprogrammer

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Re: Arnold's take on the MEM Corliss
« Reply #51 on: February 16, 2013, 08:36:50 PM »
Glad you got some time in the shop Arnold.
Nice explanation too. Thanks.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline b.lindsey

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Re: Arnold's take on the MEM Corliss
« Reply #52 on: February 16, 2013, 09:40:48 PM »
Nicely done Arnold, and as usual, very well documented also.

Bill

Offline vcutajar

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Re: Arnold's take on the MEM Corliss
« Reply #53 on: February 16, 2013, 09:54:52 PM »
Always great to see your progress on this build Arnold.

I finally managed to find a slice of mild steel for the flywheel and most probably next week I will start a thread on another MEM Corliss and then we can compare notes as I will be starting from the flywheel end of the engine.  Wish me luck.

Vince

Offline b.lindsey

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Re: Arnold's take on the MEM Corliss
« Reply #54 on: February 17, 2013, 12:57:05 AM »
I have acquired the materials for the cylinder, crosshead and flywheel, but will be watching you guys for a while yet.

Bill

Offline Don1966

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Re: Arnold's take on the MEM Corliss
« Reply #55 on: February 17, 2013, 01:08:41 AM »
Nice progress Arnold, and you must of gotten a new camera. Those photos are superb and well documented too.

Offline steamer

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Re: Arnold's take on the MEM Corliss
« Reply #56 on: February 17, 2013, 08:21:12 AM »
Great write up Arnold!   Norm used to give me the "measels" on a regular basis...I got one of these...and it works great!  especially with brass!

http://www1.mscdirect.com/cgi/NNSRIT2?PMAKA=02599041&PMPXNO=4761429&cm_re=ItemDetail-_-ResultListing-_-SearchResults


Poke around...I'm sure someone has one in your neck of the woods.....

Dave
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Damned ijjit!

Offline arnoldb

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Re: Arnold's take on the MEM Corliss
« Reply #57 on: February 24, 2013, 12:15:30 AM »
Thanks All  :praise2:

Jo, like Tel said, I didn't want that ring slapping around.  You shouldn't have mentioned that good tap of yours - it jinxes it  :LittleDevil: .  The #2 2mm tap I broke has a whole story behind it...  The only tap I ever broke before this one was also a #2 2mm - in some work-hardened stainless.  The first cut this one made was right trough that same stuff to finish that hole, so it may have been slightly doomed right from the offset  :) .

Good luck Vince  :ThumbsUp: - or rather, Happy Machining!  Yes, I'm following along, and all of us that's busy building it can compare notes  :) .  Once I get around to the flywheel, things may just involve a lot of heat and a big hammer to start off with...  I'm struggling to find material for it locally, and my budget's a bit tight at the moment, so I'll have to improvise a bit...

Bill, you're doing a great job on the Wright Brothers 1903 - finish that one off first  :ThumbsUp: .  The Corliss is still untested, so it might be good to check things out before you start on it.

Don, not a new camera - the same one, still with the broken corner  ;) The only difference is I have to take the photos from a bit further away compared to my previous builds, as the parts are so much bigger.  The cylinder block on its own is bigger than a couple of engines I've built  :facepalm2:

Dave, thanks bud, but nothing like that here on the savannah.  I have a sheet of perspex that I got especially for making up a chip-screen - but that's just another round tuit...  The only times I remember I need to make it is when a job like this comes along on the lathe, or when I forget to check which way the chips will go when fly-cutting with a carbide tool on the mill  :Lol:

Progress is a bit slow on the build, but I've had a couple of challenging "work" work assignments thrown my way.  Last Sunday, I took the day off engine building for some good old-fashioned book studying.  I planned a full day in the shop today, but while running some errands this morning, I got a call from a friend who needed some help.  Family and friends take precedence, so I only ended up with half the shop session I had planned.

I started off with centering the rotary table on the mill, moved the 4-jaw chuck to the rotary table on the mill, and drilled the mounting holes in the flange:

You might notice the piece of wire holding the "parallel" (packing as Tel called it) is gone here.  I needed to tap the packing around a bit to prevent the drill catching on it when breaking through the holes.  HSS drills don't like drilling into hardened bearing shells.

Back to the lathe, and I used a grooving tool to trepan a ring into the workpiece at about 1mm larger in diameter than needed.  I wasn't feeling in the mood to grind up a new toolbit for this job, and this grooving tool had just enough clearance on the "outside" side at this diameter, though it wouldn't do the job completely.  It also does not have a very deep sharpened reach, so when I saw it starting to raise a burr on the inside ring, I stopped:


With the bandsaw in vertical mode, I cut away most of the outside.  The groove made things easier to follow and get fairly close.  While the bandsaw blade can follow a slight curve, this ring is much too small for it to follow, so I cut away things in sections; corners first at about 45o to just intersect with the groove, then the smaller left-over bits either side and so on:

I didn't want to leave too much "meat" on the ring, as the next step was soft-soldering it to the "pipe" section.  The tin/lead solder I used is not very strong, and while more than adequate for this specific application in it's final use, it would likely not stand up to machining too much of an interrupted cut to get things to size.

Next up, the soldering.  After cleaning oil residues of the two pieces with some methylated spirits, I just coated the inside of the ring with some plumbers' flux, stuck the bits together, checked alignment of the slots in the pipe section to the holes, and added a ring of solder:

Can anybody spot the boo-boo about to happen here ?  :-[

A bit of heat from the plumber's torch from below had the solder flowing and the joint made - definitely not as pretty as I'd hoped, but it would do:


Spotted the boo-boo yet?  No?  The "pipe" section was upside-down.  The grooves in the "pipe" section is offset closer to one end, and I'd gone and soldered it in the wrong-way around  :???: .  So I re-heated everything took it apart, wiped away as much of the solder as possible with a bit of kitchen paper, and re-soldered it the correct way around.  Yippee... Job done!  Uhrm... Oops... No...     Rats  :facepalm: I didn't check the alignment of the grooves in the pipe section relative to the mounting holes in the flange  :lolb: Stupid bugger :insane: .  So once again a bit more heat till the solder flowed, and I rotated the pipe section with a leather glove to match up correctly with the mounting holes ,purely by eyeball MK1.  This is not overly critical - the cross-head has a lot of contact area in the pipe section of the cross-head guide, so if it looks OK it should be OK.  The critical bit here is that the pipe section be very square to the flange, and the inside lip I machined on the flange earlier helped with this.

So, after all the soldering boo-hah, I finally got the workpiece back on the lathe to turn the flange to the correct diameter.  I clocked it up in the 4-jaw chuck again:

There was no real need for this; I could just have used the self-centering 3-jaw, but I like a bit of a personal challenge.  And anyway, my 3-jaw chuck is out by miles and a bit bell-mouthed, and I'd rather take a bit of accuracy here.  With the cut-outs on the pipe section, the 3-jaw would also be more inclined to distort the workpiece.

One bit of kit I got with my lathe is very nice indeed - though I haven't mentioned it very much.  The revolving tailstock center has interchangeable bits, and besides the normal sharp 60o center, it has a larger cone center and so on.  I fit the cone center for the next step; it's larger than the bore in the pipe and added some rigidity:


And turned the flange down to size.  Light cuts, so as not to break the soft soldered joint:


Finally, I had the cross-head guide done:


This engine is taxing my available material, so I settled on some 25x5mm flat bar to start the steam and exhaust cover plates from:


Those bits were machined down to length and width (60x23mm), and then I spotted the hole positions for drilling, leaving a lightly spotted hole in the center for more machining later on:

 :wallbang: I really need to get myself a set of parallels; that lot was just mounted by fingertip-feeling across the top of the vise's fixed jaw.  It's not good practice and a nonchalant personal vice I need to address...

After a bit of drilling, it looked like this:


The second one followed, and I two covers-in-making.   A bit thick, but in progress.  The result of today's work:


Not a true assembly shot, but this is what things looks together like right about now:


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 zeeprogrammer

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Re: Arnold's take on the MEM Corliss
« Reply #58 on: February 24, 2013, 12:47:39 AM »
Progress is a bit slow on the build, but I've had a couple of challenging "work" work assignments thrown my way.

Oh whine whine whine. A bit of 'work' getting in the way? You've been throwing that up a bit too often lately.  ;D Actually, I'm rather envious. I'm suffering the same issues but you still seem to manage some shop time.  :cussing:

Can anybody spot the boo-boo about to happen here ?  :-[

Not me. Never seen a boo-boo about to happen from you.  ;D

Spotted the boo-boo yet?  No?  The "pipe" section was upside-down.  The grooves in the "pipe" section is offset closer to one end, and I'd gone and soldered it in the wrong-way around  :???: .

You apparently have 'zeepitis'. I didn't think it was catching...much less transferable via forum. Sorry about that.

I sure enjoy reading your posts Arnold. I enjoy learning your machining techniques as well as your reaction/response to 'challenges'.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Don1966

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Re: Arnold's take on the MEM Corliss
« Reply #59 on: February 24, 2013, 12:52:58 AM »
Arnold , another great post and well documented photos. Bummer about the flange it happens to all of us.  I usual find myself doing stupid things when I have to many other things on the brain. Or I just get in too much of a hurry. As always love to follow your progress.

Don