Author Topic: Arnold's take on the MEM Corliss  (Read 134599 times)

Offline Don1966

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Re: Arnold's take on the MEM Corliss
« Reply #30 on: January 28, 2013, 06:44:36 PM »
Looking good Arnold, and that is a bummer to break a tap with all those holes to drill and tap. I think I would of loss my cool on that one. Good save though. I will be following you closely and enjoying your work as always.

Don

Offline Alan Haisley

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Re: Arnold's take on the MEM Corliss
« Reply #31 on: January 28, 2013, 08:53:50 PM »
Arnold, all of your pictures zapped out. They were there yesterday when I looked at this thread.
Alan
Near Raleigh, NC, USA

Offline arnoldb

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Re: Arnold's take on the MEM Corliss
« Reply #32 on: January 29, 2013, 03:48:31 PM »
Thanks All  :)

Tel, you should know by now that farm implements affects shop time...  Are you over that heat wave ? - it's reached right up here...

Rick, this was a small amount of drilling... Wait till you see what Jo have in mind  >:D .  I'm quite fortunate with taps; only ever broken one.  But I follow a rigorous tapping regime.  The metric taps I use have 3 taps per set - and they don't quite follow the US / UK tapping practice.  The first tap is a starter tap, and by itself pulls and starts a shallow thread nice and square in the hole.  The second tap is not to full thread size, but follows the starter tap's thread easily and taps easily.  The third tap takes the thread to full size.  I use these taps each in turn, without skipping any one of them on a hole, and as a result I get good results tapping holes.  As they don't do full thread diameters, I don't need to follow the practice of tap a bit, twist back, tap a bit.  They just screw right in without any stopping, and right out again.  So even using all three taps, things are relatively quick.

Alan, the pictures should be back now.  My hosting site applied my annual domain registration fee to the wrong account, and as a result my domain expired - when that happens they take the domain off-line :facepalm2: - fortunately they now found the accounting error and reinstated my domain.  So the piccies are back, and should be safe for another year.  They'd better not stuff up next year; I'll check up on them better anyway  :slap:


Bob (Maryak) made up a slightly revised drawing of the cylinder showing measurements to drill the port holes before machining out the steam & exhaust chest pockets.  Unfortunately that email is sitting on my home PC now, and I'll only be able to access it again at the end of the week. Basically I'm going about getting the steam passages drilled the hard way, but I have a couple of ideas.  All that have to wait till the weekend though.  I considered bringing the cylinder block and taps along on my business trip, but somehow I don't think the hotel would be happy with the smell of tapping fluid pervading the room  >: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 Maryak

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Re: Arnold's take on the MEM Corliss
« Reply #33 on: January 29, 2013, 10:24:36 PM »
Arnold and All

To save you the trouble, I have attached the revised page here.

Best Regards
Bob
Если вы у Тетушки были яйца, она была бы Дядюшкой

Offline arnoldb

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Re: Arnold's take on the MEM Corliss
« Reply #34 on: February 03, 2013, 04:42:21 PM »
Thanks Bob  :NotWorthy:

Saturday was a lost cause on machining... It reached all the way to 39C here, and I just don't go to the shop when it's that hot.
Today was a bit cooler, so I got in a bit.  Not much to show for it though...

The cylinder block still needed the port holes, and silly me had to go about it the hard way, as I didn't think things through carefully enough right from the start.

First of all, I needed a way to set the cylinder block at the correct angle to drill the port holes - that's 15o .  One of the items lacking in my tooling area is an angle vise - so I had to improvise a bit.  I grabbed a block of 10mm flat bar, and milled one end and one side nice and square.  Then I roughly sawed off a tangent section at about 15o.  I used my precision protractor to set that up in the mill to mill the block to a fairly accurate 15o angle:

That protractor is a prized bit of tooling in my shop.  The set-up trapped it there, but it was easy to take out by just loosening the adjustable arm and pulling it out.  There's no way I'd leave it in place while milling the workpiece.

After milling the block of steel to size, I tested it against the protractor again after I removed it from the vise - just to make sure it didn't move while milling the tangent:

 ;D I now have a half-accurate 15-90-75 degree triangle added to the shop tooling.  Not high precision, but it'll do for most jobs that come along.

While on my business trip this week, I had lots of time to think while driving.  The simplest solution I could come up with for drilling those port holes without the drill wandering at the start was to make a drilling guide from some 6mm silver steel - that's a close fit in the valve bores.  I grabbed a bit of silver steel, and accurately cross-drilled the 1.6mm hole through it after skimming a flat on it with an end mill:


Setting up for drilling the port holes was not too difficult.  I set the workpiece op on the newly made triangle, and also set the vise stop to block both the triangle and the workpiece:


Then I fiddled with the x axis until a 1.6mm drill easily passed through the drill guide - I did this with the drill guide inserted into the valve bore, but with the drill and hole outside of the block so I could check for alignment and deflection:


Then I proceeded to drill the holes - by moving the y axis as needed and then manually twisting the drill chuck while twiddling the guide into position, and then starting the mill:


Things didn't turn out quite as well as I'd hoped, but it should work.  It would have been better to pre-drill all the holes in the drilling guide rather than fiddle with it for each hole in the block:




Only once I was done with the holes, I realized I should have drilled them 1.5mm rather than 1.6mm...  Oh well, the engine should breathe easier.

As a last drilling operation on the block, I drilled the left hand side for the cylinder cover.  Easy-peasy; center on the hole, and let the DRO calculate the bolt circle.  I went for the smaller PCD as per the plans on this one:


Now all that remains on the block is tapping, honing the bore, and a lick of paint.
"All"...  Just 52 x M3 holes and 32 x M2 holes to tap...  Each hole three times with a starter, middle and bottom tap...  I feel an interruption coming on for a quick tooling project  :naughty:

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 mklotz

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Re: Arnold's take on the MEM Corliss
« Reply #35 on: February 03, 2013, 04:50:19 PM »
Very clever setup, Arnold.  Obviously you thought that one through thoroughly before starting.

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Offline vcutajar

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Re: Arnold's take on the MEM Corliss
« Reply #36 on: February 03, 2013, 04:57:45 PM »
Arnold

Following you like a shadow and realising that steam engines are a different kettle of fish from i.c. engines.  New terminology to learn.

I also use 3 set metric taps and never realised that they are self-centering.  Good to know.

Yesterday I went to my favourite metal supplier to see if I can get the required material for the flywheel and found out that the largest diameter he stocks is 120mm.  That put a damper to my plans.

Vince

Offline propforward

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Re: Arnold's take on the MEM Corliss
« Reply #37 on: February 03, 2013, 05:00:43 PM »
That is a very well thought out approach - very impressive.
Stuart

Online Jo

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Re: Arnold's take on the MEM Corliss
« Reply #38 on: February 03, 2013, 05:06:58 PM »
Now all that remains on the block is tapping, honing the bore, and a lick of paint.
"All"...  Just 52 x M3 holes and 32 x M2 holes to tap...  Each hole three times with a starter, middle and bottom tap...  I feel an interruption coming on for a quick tooling project  :naughty:


So have you already done the studs  for it :naughty:
----
Nice progress, those ports are likley to be the thing that puts most people off with a corliss :ThumbsUp:.

Jo
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Offline NickG

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Re: Arnold's take on the MEM Corliss
« Reply #39 on: February 05, 2013, 09:29:16 AM »
looking good Arnold

Offline arnoldb

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Re: Arnold's take on the MEM Corliss
« Reply #40 on: February 06, 2013, 04:57:54 PM »
Thanks All  :praise2:

Vince, the taps do tend to pull themselves straight if you start with the first one.  Just use a light touch in sort-of keeping it aligned at the start.  Not much use for shallow holes though; sometimes the starter tap's point will bottom out before it's even started to cut the thread.  That's when I resort to a tapping block to keep the tap straight.  The terminology is slightly different, but not really that much - most of it is based on the differences in design between IC and steam engines.

Quote
So have you already done the studs  for it :naughty:
Sadist  :ROFL: How did you know I've got 2.5m of 3mm 303 rod? The 2mm studs I'll make from full threaded sections though.  Can't ruin my reputation for being a lazy rotter  ;)
If it weren't for the fact that the tapping fluid vapors could be very harmful to Shrek the parrot, I'd have brought the small lathe into the house for that already... There's LOTS of space on the dining room table.

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 arnoldb

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Re: Arnold's take on the MEM Corliss
« Reply #41 on: February 09, 2013, 07:08:02 PM »
On to today's bit - there's not much to show for half a day's shop time though...

I started on the crosshead guide.  With the going-rate of steel here I tend to be frugal, and unless it's absolutely necessary that a workpiece be made from one solid piece and mostly turned to chips, 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.
With a lump of the 32mm bar chucked up, I gave it a single pass to under-cut the mill scale - that stuff toasts a HSS toolbit very quickly if you let it "rub" against it:

After a quick re-sharpen of the toolbit on the oil stone, I turned it down to 27mm.

Then the parade of drills started.  A 4.5mm pilot hole as deep as I could get it.  The 4.5mm drill bit is much too short for the entire job, but a good start.  Why 4.5mm? - well, it's one of the lesser-used drills in my drill index, so nice and sharp, and being one of the more "standard" sizes, cheap to replace when it dulls.  It's also fairly stiff and not inclined to wander too much in the lathe.  I followed that by a bit of a hog - a 13mm drill till it bottomed out on the pilot hole.  My old Myford happily breezes through this type of operation, but once the big drill hits the bottom of the pilot hole, one really needs to force the tailstock handwheel to carry on.  The lathe will do it, but I can't help but feel the wear on the tailstock feedscrew and nut gets excessive, so at this point I ruffled through the drill index to find a smaller drill that would go all the way through the workpiece.  The 8.5mm drill did that.  What's nice about having the bigger hole for most of the way already, is that the swarf from the 8.5mm drill had lots of room in the 13mm section, so less "pecking" needed to go all the way.  Once the 8.5mm drill was all the way through, I followed it with the 13mm drill again all the way through. I only have two drill bits above 13mm - a 16mm and a 19mm - so these followed.  Here I'm getting ready to poke the 19mm drill through:

While it was not strictly necessary to drill the hole all the way through the workpiece, there was some boring to follow to get to the required 21mm diameter.  The through-hole meant that swarf from the boring operation could also go through the hole and into the lathe spindle - making things just a bit easier than on a blind hole.

After all that drilling, the lathe's motor was running a bit warm, so I gave it a break and started tapping some holes in the cylinder block.  I was considering making up a tapping stand first, but I'd rather like to carry on with this project and do the tapping stand as a separate project:

 ::) The M2 tapping session came to an abrupt end - broke the number 2 tap in the third hole I was tapping.  Fortunately it snapped where the threaded section on the tap becomes plain, so there was enough left sticking out the hole to just turn the left-over bit out with pliers.  The other M2 tap I broke a couple of years ago was unfortunately also the number 2 - so I couldn't even fall back on the old set to continue...  I just hope the local supplier have stock.

Back to the crosshead for boring.  I tried with one of my existing 6mm boring bars, but right at the start of the start of the cut it chattered more than the Mad Hatter.  This would never survive the looking glass, so I spent a couple of minutes in Wonderland to try and figure things out.  Right.  A looong bore. (Well, in my experience of machining anyway).  There's a lot of workpiece hanging out from the chuck - so some support needed as well.  And a rigid tool good for four inches of work. 
A quick job on the band saw and milling  machine left me with a bit of 16mm silver steel rod cross-drilled for 4mm HSS stock and a 3mm grub screw to keep it in place.  A couple of flats milled on the  other end encouraged it to fit in QCTP holder.  To add a bit of rigidity to the workpiece, I broke out the lathe's fixed steady, set it's fingers up close to the chuck, and then clamped it down close to the end of the workpiece on the lathe bed and added some thick oil to lubricate it:


After boring out the workpiece to 21mm from the 19mm drilled hole, I ended up with a bore finish that's sort of "OK":

Not quite up to the standard I expect from myself, but this is a new learning curve for me, so I'll settle for it.  The bore looks a bit rough in the photo, but feels smooth, and should work.

Like I said, not much to show for a bunch of hours in the shop, but some progress.

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 #42 on: February 09, 2013, 07:57:39 PM »
Nice post Arnold. I liked the explanations.
Sorry about the tap.
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Offline vcutajar

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Re: Arnold's take on the MEM Corliss
« Reply #43 on: February 09, 2013, 09:49:11 PM »
Thanks for the update Arnold.

Always look forward for the weekend to arrive to see your progress.

Vince

Offline Maryak

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Re: Arnold's take on the MEM Corliss
« Reply #44 on: February 09, 2013, 11:58:19 PM »
Good Job Arnold  :NotWorthy:

It's nice to see the fruits of our labours in action and it gives us an idea of what's required tooling wise to build the engine.

Best Regards
Bob
Если вы у Тетушки были яйца, она была бы Дядюшкой