Author Topic: Arnold's take on the MEM Corliss  (Read 134673 times)

Offline Maryak

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Re: Arnold's take on the MEM Corliss
« Reply #285 on: June 24, 2013, 08:42:57 AM »




That's why Arnie showed us his shoes  :lolb:

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

Offline swilliams

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Re: Arnold's take on the MEM Corliss
« Reply #286 on: June 24, 2013, 08:58:19 AM »
 :lolb: Looks like a better present for the significant other than an B&D electric drill Bob  :Lol:

Steve

Offline arnoldb

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Re: Arnold's take on the MEM Corliss
« Reply #287 on: July 01, 2013, 06:31:39 PM »
Thanks for looking in all  :praise2:

Jerry, you just made me feel very blonde  :facepalm: - of course that's the easy way  :ThumbsUp:

Steve, I didn't even notice my shoes in the shot...  It's a good thing I wasn't wearing the pair Bob suggested  :naughty: ; Just imagine the ribbing I'd have gotten from everyone over the colour of my toe-nail varnish  :Jester:

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 #288 on: July 06, 2013, 08:30:51 PM »
Had a couple of hours in the shop today.

First up was a a bit of 7mm brass rod turned down to 6mm with a 3mm step at the end that was threaded with a tailstock die holder:


That was cross-drilled 3mm in the mill:


Then parted off, chucked up with a 3mm collet, center drilled, and drilled 1.1mm:


A 1.4mm tap followed, officially making this the smallest hole I'd ever tapped.  The small drill chuck's shank was left _just_ free to rotate in the tailstock drill chuck, and it's surprising how little torque it took to tap the hole; just light finger-tip action:


Last week when I collected my new pair of glasses at the optician, I chatted up the lovely lass who works in the front office, and asked if it would be possible to buy out some M1.4 and M1.6 screws from them.  I soon had a packet with about 10 each in my hand, and after solemnly having to promise that I won't sell them for beer money or set up a competing shop, the price was "no charge".  I wish there was more places like this optician - not because of the freeby; that's cherry on the cake - but because they are one of a VERY few places locally that provide efficient, friendly and professional customer service; it's actually nice to go there.

Anyway, the screws I got were all 8mm long, so I had to shorten one a bit.  I tried it with the doohickey (it's not quite a true lantern chuck) that I made sometime to shorten M2 screws.  It was a bit of a loose fit, but worked:


I added about six turns of M3 thread to a length of 3mm stainless steel rod for a start on the "eccentric to disk rod", and ended up with this lot.  I forgot to take the tap out of the picture:


The 3mm stainless rod needs to have a bit of a bend in it.  I checked on the engine itself, and somewhere I must have strayed from the plans a bit; instead of the 7.5mm called for, I only needed about 4.5mm...  So I set two bits of 5mm brass flat bar (thicker than the 4.5mm to compensate for some "spring") up on the bottom of the mill vise, together with the rod - all just judged by eyeball MK1, as there is no super-precision needed for this step:


The vise was tightened up, and once released, there was a step on the rod:


I faffed around with some 2mm stainless steel rod and a 2mm tail stock die, and soon had these bits to connect the clevises of the two eccentric rods to the pivot lever:


Next up I wanted to make a start on the valves.  When checking my stock, there was not enough 6mm stainless rod, so I'll have to visit the metal-candy shop this coming week.   Things are starting to come together slowly, but there's a lot of detail left to do.  I pulled a "Jo" and started on some M3 studs to finish the shop session:

More sizing and threading needed on those....

A final overview of the engine thus far - no studs included, as those are half-screwed partially done:


So far, the parts were quite large in my experience but there's a lot of fiddly small bits coming up 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 Jo

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Re: Arnold's take on the MEM Corliss
« Reply #289 on: July 06, 2013, 08:49:38 PM »
.....  I pulled a "Jo" and started on some ....studs


Sorry Arnold I don't want to spoil your boasting but for the record you will be pleased to know that you have not (yet) pulled me  ;). The competition at the moment is rather lacking  :shrug: but concerningly hopefully after the 21st that will increase   :mischief: :lolb:

A M1.4 is equivalent to a 12BA  :whoohoo: which I know is fun there was lots and lots on my Lady S (my avatar).

Nice lantern chuck  :ThumbsUp: Small fiddly bits are fun  ;D

Jo
Usus est optimum magister

Offline Tennessee Whiskey

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Re: Arnold's take on the MEM Corliss
« Reply #290 on: July 06, 2013, 09:23:34 PM »
Looking great Arnold. Nice score at the opti. You single blokes can score all the deals. Just how lovely was the lass now Arnold 8)?

Eric


Offline NickG

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Arnold's take on the MEM Corliss
« Reply #291 on: July 06, 2013, 09:54:57 PM »
Yeah, that's why he really wants all the shops to be like that one! So didn't you let on that you were building a model engine and start explaining how the corliss mechanism works?!

Offline vcutajar

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Re: Arnold's take on the MEM Corliss
« Reply #292 on: July 06, 2013, 10:41:08 PM »
Arnold, you must have switched on all your charm to get away with all those free taps.  Seriously that was a magnificent score.

Vince

Offline ozzie46

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Re: Arnold's take on the MEM Corliss
« Reply #293 on: July 06, 2013, 10:51:38 PM »


  That is looking beautiful Arnold. I can't hardly see that small of a screw let alone try to tap threads for one.
  Although I'm going to have to try a 0-80 or 1-72 soon for a carb. Is there a smiley for "frozen with fear"?

  Ron

Offline mklotz

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Re: Arnold's take on the MEM Corliss
« Reply #294 on: July 06, 2013, 11:11:22 PM »
  Although I'm going to have to try a 0-80 or 1-72 soon for a carb. Is there a smiley for "frozen with fear"?

Make yourself some guided tap holders, e.g....

http://www.modelenginemaker.com/index.php/topic,274.0.html

and you'll significantly increase your chances of success.
---
Regards, Marv


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Offline arnoldb

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Re: Arnold's take on the MEM Corliss
« Reply #295 on: July 15, 2013, 12:14:47 AM »
Thanks Jo.  Pity you're so far away; you'll just have to take your chances on the 21st  :LittleDevil: .  The "Lantern" chuck works, but I need to get my finger out and build a proper kit for the different screws I use; on more than one occasion I've wished I had a better selection, and it's about time I built a decent useful set  :ThumbsUp: .  In fact, after the Corliss, there's a lot of tool-related work in my future...

Eric, Thanks.  Well, she's definitely worthy of the eye...  but unfortunately some jewelery she wore told me not to go too far  ;)

Cheers Nick - I just told her it's for building model engines; I skipped the Corliss description and rather joined in on how to spend the bit of extra cash-in-hand we all have available in Namibia after a lowering of income tax rates last month  ;)

Thanks Vince - though the score wasn't quite that big - just a handful of screws.  The taps I bought through this same optician about two years ago - albeit at a very reasonable price.  Unfortunately they can't get die nuts the same way...  And I'll bide my time; it may just be possible to get some very thin silver solder and silver solder paste through them as well - of late, I frequently pass the shop on my way to some of my clients, and once I see they're very quiet, I'll pop in and discuss that; don't want to make a nuisance of myself  :)

Ron, thank you.  Like Marv mentioned, when they get smaller you need a tap guide or tapping stand of some form.  And light fingers; the finer the threads, the lighter the touch you need.  Don't be afraid of the small sizes; I know it's daunting - four odd years ago I thought an M3 was really small; in fact I commented on that on my "first running" engine build.  Now M3 seems positively large, M2 have become a "normal" size, and less than that are just a new experience requiring some thought before-hand.  In fact, once I can get my fingers on M1 taps, I'll happily give them a go and build one of George Britnell's small engines.  The screws do get a bit small, and a pair of tweezers starts to become mandatory.  A good magnifying glass should help as well; in fact, I'm in the market for one of those myself :D


Shop time's been a bit scarce of late, but I eventually got some this afternoon.  During the week I managed to pop over to a supplier, and purchased a meter of  6mm stainless steel rod.  Somehow, the rod included two 50x50x50mm aluminium cubes from the off-cut bin as well; those just jumped into my grubby paws for some unfathomable reason ::) .

So I started off with some sections sawed from the stainless rod:


Those were faced of on one side each on the lathe.  I've not done much "multiples of the same part" work yet, but for the rest of the operations it seemed prudent that I set up some way of work-holding to make the four valves.  The tooling plate would work, so on to the mill with the tooling plate mounted in the vise.  A later photo shows more detail; this blurry one hides some of the setup, but essentially I screwed some cap-screws straight into the plate to use their heads to locate the workpieces against.  The clamp on the right-hand side screwed directly to the plate acts as a depth-stop to butt the workpieces up against.  Then I added the two clamps to hold the workpieces down - at a slight angle so that they would both hold the material down on the plate and also against the heads of the cap screws on the plate.   :-[ Confusing - I know, and also, there's a booboo waiting to happen; see if you can spot it:

Anyway, that lot worked to mill the workpieces to the correct length.

I changed the set-up slightly for the port cut-outs; you'll notice the scrap bit of aluminium I added for a better depth-stop to mill out the valve sections; things were a bit tight on the left-hand side, but OK:


On to the next machining operation.  The workpieces needed 1.5 x 1.5mm slots on the valve-train side, parallel to the cut-outs in the valves.  To set this up, I used the shank of a 3mm drill in the cut-outs to locate things.  Here you can also see one of the cap head screws I bolted down to the plate to guide things; the other is just barely visible below the clamp:


With the second clamp added, I started making the slots with my 1mm  and 0.5mm slitting saws ganged together:

If you look carefully, you might see the boo-boo happening.  It's easy in retrospect, but I didn't see things coming, except that the slots all ended up more off-center on each one, even though I'd taken good care to center things when I started...

Anyway, I slotted all the valves on both sides - slotting on either side is not on the plans, but will make setting the valve timing easier later on in the build.  I ended up with this lot:

Looks OK - only if one would consider a surface-finish in the cut-outs left by some metal-munching rodent acceptable...

And the lot in the photo above is far away from good enough...  I've alluded to the booboo, so it's time I explain the predicament to those that have not fallen off their chairs laughing yet.  The back supports of the clamps were pressing on the mill vise jaws rather than on the tooling plate itself, so, as I tightened each workpiece in turn, the tooling plate lifted out of the vise.  Have a look at the second photo in this post; the tooling plate is pretty much flush on the vise jaws, and on the last one, it's lifted nearly 0.5mm above the vise jaws...  I didn't expect that - only in retrospect does it make sense...  So I ended up with badly of-center slotted valves.  Bummer.  Lesson learned though.  Re-Do needed, and I might just pull another "Lazy Arnold" - and make the valves in one piece...

Even though the parts made today sucks, I still tried them in the engine.  Things really sucked after that - much to my surprise  :o .  This was the first time I got to try out the cylinder with sort-of valves in place.  With all the valves in a closed position, the crank-side pack nut made nice suck-blow sounds when I spun the flywheel.  And on the other end, with the palm of my hand covering the cylinder opening, there was enough suck and blow coming from the piston strokes to really feel.  And with the one of the intake valves opened a fraction, there was a very nice Shushhh Shushhh steaming-like sound.   Like mentioned; I didn't expect things to suck (or blow) that much...  The piston still needs a ring, the packing nut needs packing and so on, but for now, I'm happy.  Things may look cruddy, but she just might will end up a runner  :cartwheel:
 

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 #296 on: July 15, 2013, 02:47:36 AM »
Good Going Arnold,  :NotWorthy:

Down to the nitty gritty parts now. I must admit I have everything crossed that all the angles are correct between the eccentric and the valve.

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

Offline ths

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Arnold's take on the MEM Corliss
« Reply #297 on: July 15, 2013, 04:31:09 AM »
Hi Arnold, it took me a while, but I finally saw what you meant. Bummer, but at least you know why. All in all though, good news!

Cheers, Hugh.

Offline Captain Jerry

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Re: Arnold's take on the MEM Corliss
« Reply #298 on: July 15, 2013, 04:51:36 AM »
Arnold

Of course is will run.  It has to!  Each valve is individually adjustable!  It may take a little fiddling but that is part of the fun.  Once you get the simplified non-release version working, it is only one more step (more or less) to set up the governor controlled release trips.

It is looking very good and your almost there.

Jerry
NOTARY SOJAK

There are things that you can do and some things you can't do. Don't worry about it. try it anyway.

Offline b.lindsey

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Re: Arnold's take on the MEM Corliss
« Reply #299 on: July 15, 2013, 12:04:49 PM »
Not all bad news Arnold, bummer on the vise boo-boo, but at least you know the valves perform their function nicely which should make the re-do easier to swallow :)  Its all really coming together though very nicely!!

Bill