Author Topic: Elmer's Oscillating Cylinder Engine #42  (Read 5541 times)

Offline EricB

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Elmer's Oscillating Cylinder Engine #42
« on: March 02, 2021, 09:08:51 PM »
At long last I've started on my second steam engine. I have another PMR casting kit sitting on the bench but I decided to try one from scratch instead. I didn't think this engine would be too complex. I'm down for materials and I managed to break my lathe drilling out the cylinder, but here's what I have so far.

I was using a 3/8" drill for the final pass in the cylinder before finishing with a boring bar. The drill caught in the brass and quickly welded the MT0 chuck adapter into my tail stock ram.  :'(

« Last Edit: March 02, 2021, 09:16:42 PM by EricB »

Offline cnr6400

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #1 on: March 02, 2021, 10:02:17 PM »
If the ram is through-drilled, just heat the end of the ram with the stuck arbour in it close to red heat, and bash the arbour out with a hammer and a suitable sized punch. Hold the ram in a sturdy vise with soft jaws in it for the bash fest.

Is the ram from a Sherline or is it a Chinese import? If Sherline or Taig or other make of lathe made in USA you may be able to get a replacement ram. With Chinese ones you might be able to get a new ram from the importer but it may or may not fit. Seems parts interchangeability is not a given with the China machines, although purchase price is low.
« Last Edit: March 02, 2021, 10:08:25 PM by cnr6400 »

Offline gary.a.ayres

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #2 on: March 03, 2021, 12:04:54 AM »
Commiserations on the mishap. Part of the territory, but a real pain when these things happen.

Some nice parts you have made already though...

Offline EricB

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #3 on: March 03, 2021, 01:16:07 AM »
If the ram is through-drilled, just heat the end of the ram with the stuck arbour in it close to red heat, and bash the arbour out with a hammer and a suitable sized punch. Hold the ram in a sturdy vise with soft jaws in it for the bash fest.

Is the ram from a Sherline or is it a Chinese import? If Sherline or Taig or other make of lathe made in USA you may be able to get a replacement ram. With Chinese ones you might be able to get a new ram from the importer but it may or may not fit. Seems parts interchangeability is not a given with the China machines, although purchase price is low.

I did manage to get the adapter out of the ram using the leadscrew but both the parts are ruined.

My tools are Sherline. I should have the replacement parts in a few business days. The ram is ground to fit the tailstock so I had to give them the OD for them to match it.

I just thought that if they sell a 3/8" chuck it should handle a 3/8" drill right? Well maybe not. That was the first time I tried it and probably the last.

Offline cnr6400

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #4 on: March 03, 2021, 01:44:16 AM »
Chris Rueby (code name crueby in this forum) is an expert with his Sherline tools and he could probably comment whether 3/8" drilling in brass is advisable / possible or not in your Sherline lathe.

Any twist drill as it comes from the factory will tend to snatch in brass. You can grind flats on the cutting lips of the drill parallel to the drill's axis for drills you plan to use only on brass, which will reduce the snatching tendency. However such drills will no longer cut steels well, if at all.

A better way in your machine may be to drill a smaller hole to start with and progressively bore it out in small steps to whatever diameter you need in any material. Much less risky for your machine and a lot less drama. The holes will be rounder as well.  :ThumbsUp:

Glad to hear your replacement parts are on the way. Good luck with the engine!  :cheers:

Offline EricB

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #5 on: March 03, 2021, 01:57:01 AM »
Commiserations on the mishap. Part of the territory, but a real pain when these things happen.

Some nice parts you have made already though...

Eventually I autograph all my tools!

I like the way the cylinder looks. The pivot shaft runs through perpendicular to the bore and is soldered in before turning. I'm not sure the solder filled the entire joint. The cutting tools made knocking sounds when boring through that area.

Offline crueby

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #6 on: March 03, 2021, 02:16:27 AM »
Chris Rueby (code name crueby in this forum) is an expert with his Sherline tools and he could probably comment whether 3/8" drilling in brass is advisable / possible or not in your Sherline lathe.

Any twist drill as it comes from the factory will tend to snatch in brass. You can grind flats on the cutting lips of the drill parallel to the drill's axis for drills you plan to use only on brass, which will reduce the snatching tendency. However such drills will no longer cut steels well, if at all.

A better way in your machine may be to drill a smaller hole to start with and progressively bore it out in small steps to whatever diameter you need in any material. Much less risky for your machine and a lot less drama. The holes will be rounder as well.  :ThumbsUp:

Glad to hear your replacement parts are on the way. Good luck with the engine!  :cheers:
Yup, I've had problems with drills much over 1/4" overpowering the taper adapter on my Sherline too, brass or steel. The MT0 is pretty small for that much torque. Never had it gall the parts together though. For the larger drills, I usually either start at 1/4" and step through the larger sizes, or drill 1/4 and use a boring bar to take the hole out the rest of the way. The boring bar usually gives better results, the larger drills tend to wobble slightly and give odd shape holes.
Chris

Offline EricB

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #7 on: March 03, 2021, 02:17:47 AM »
Chris Rueby (code name crueby in this forum) is an expert with his Sherline tools and he could probably comment whether 3/8" drilling in brass is advisable / possible or not in your Sherline lathe.

Any twist drill as it comes from the factory will tend to snatch in brass. You can grind flats on the cutting lips of the drill parallel to the drill's axis for drills you plan to use only on brass, which will reduce the snatching tendency. However such drills will no longer cut steels well, if at all.

A better way in your machine may be to drill a smaller hole to start with and progressively bore it out in small steps to whatever diameter you need in any material. Much less risky for your machine and a lot less drama. The holes will be rounder as well.  :ThumbsUp:

Glad to hear your replacement parts are on the way. Good luck with the engine!  :cheers:

I've thought about modifying a set of drills for brass. I just haven't got there yet. Perhaps now's the time.

I was going up in steps but my index skips from 5/16 to 3/8. I didn't even think about the depth at the time but that's a .062" cut. No wonder it pulled loose.

Well I'm still learning.

Offline EricB

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #8 on: March 03, 2021, 02:45:59 AM »
Yup, I've had problems with drills much over 1/4" overpowering the taper adapter on my Sherline too, brass or steel. The MT0 is pretty small for that much torque. Never had it gall the parts together though. For the larger drills, I usually either start at 1/4" and step through the larger sizes, or drill 1/4 and use a boring bar to take the hole out the rest of the way. The boring bar usually gives better results, the larger drills tend to wobble slightly and give odd shape holes.
Chris

Galling only took a second. The drill caught, spun the chuck, and locked up before I could find the off switch.

I made a boring bar holder for my first engine build. No excuses for not using it.


Offline cnr6400

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #9 on: March 03, 2021, 04:16:44 PM »
Just a thought - don't throw away the damaged ram if the internal thread at back end is still serviceable. If the thread is OK, you could use the damaged ram to mount other attachments like a drill pad, tap holder, die holder, multi tool turret etc in future. The M0 taper could be bored out straight to accept close fitting straight pins / spigots on the accessories mentioned above.

Your boring bar mount looks great! well done.

The great thing about engine / model making machining work is that you learn something on virtually every job whether you have been doing it 5 days or 40 years.  :cheers:

Offline EricB

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #10 on: March 07, 2021, 04:29:50 AM »
Spent quite a few hours today making little parts and fixing mistakes.

Started with the piston and rod. Everything went smooth until I tried to slide the piston through the cylinder bore. No-Go. Now I know why reamers were invented. I had left the cylinder a few thou under so I resized and squared it up with a boring head on the mill. I still need to make a new piston.

Then I made the outboard head. It started as a chunk of 1/8" x 1" bar stock. The OD needed to be 1" so I had to make it round without reducing the width. For that I super glued it to a bit of aluminum in the 4 jaw. As it got close to size I shifted the part toward the side that had the largest flat spot until the opposing flats were equally removed. Once it was to size I finshed the outer end and moved it to the mill to make the bolt holes. A little heat from a kitchen torch to break the glue then back to the lathe to finish the inside surface.

I also started a few of the steam passages in the cylinder that I could do with the tools I have on hand. I need to go shopping.

Eric

Offline EricB

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #11 on: March 15, 2021, 05:00:23 AM »
The replacement parts for my lathe arrived late last week along with some tiny end mills so I've made a little progress. I made the inside head parts and soldered them together, soldered the end onto the piston rod, and made a new piston.

Today was the two steam passages that connect to the cylinder bore and all the mounting holes for the heads and valve plate. Doesn't seem like much but it sure took all day.

I'll finish the exhaust port in the cylinder when I drill the steam holes in the valve plate.

Eric

Offline MJM460

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #12 on: March 15, 2021, 10:04:34 AM »
Hi Eric, thatís a very interesting engine.  Coming along nicely.

MJM460

The more I learn, the more I find that I still have to learn!

Offline EricB

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #13 on: March 22, 2021, 04:15:58 AM »
I have a length of 12L14 on hand so today I made the end of the crankshaft. It's amazing how much work can go into a part that's so small.

I started on the lathe with the slug offset in the 4 jaw enough to drill and turn down the boss for the big end. I then moved to the rotary table on the mill and removed the material on the straight sides and the circumference of the big end. While I had it there I drilled the hole for the connecting rod drive pin. Then back to the lathe to part off and clean up the mess that made. Finally I clamped it back on the rotary table and finished the circumference of the small end.

Sorry I didn't take pictures of the process but here are the results.

Eric
« Last Edit: March 22, 2021, 04:40:36 AM by EricB »

Offline gary.a.ayres

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Re: Elmer's Oscillating Cylinder Engine #42
« Reply #14 on: March 22, 2021, 10:56:58 PM »
Very nice work.