Author Topic: Elmer's #50 completed  (Read 311 times)

Offline sshire

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Elmer's #50 completed
« on: November 19, 2017, 11:55:21 PM »
Elmerís #50 - A Runner!

I built this engine to take a break from the S4 (Simpson and Shipton Short Stroke) which has been giving me fits. More about that another time.

My CAD/Cam software is Autodesk Inventor and, since Fusion 360 is very close in operation, I thought Iíd model a simple engine to see if a switch was reasonable.

After modeling Elmerís #50, I had a go at actually building it.

Other than the cam, nothing was done on the CNC. All Bridgeport, Grizzly lathe, etc.

Modeling the operation and orientation of the cam mechanism made understanding it much easier.

Hereís the model and the machining.


And the engine.

Best,
Stan

Online b.lindsey

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Re: Elmer's #50 completed
« Reply #1 on: November 20, 2017, 12:39:11 AM »
Very nice job Stan on one of Elmer's more unique designs. The cam is certainly an interesting feature of the model!!

Bill

Offline Dave Otto

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Re: Elmer's #50 completed
« Reply #2 on: November 20, 2017, 12:50:24 AM »
Interesting mechanism Stan, she runs nice!

Dave

Offline Kim

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Re: Elmer's #50 completed
« Reply #3 on: November 20, 2017, 02:04:38 AM »
Wow! I'll say!  This is cool Stan!  It's not just the cam, but that elliptical connection/mechanism that drives it - it makes the cam have a different radial speed at different angles of rotation.  Pretty fascinating to watch!

Kim

Offline Flyboy Jim

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Re: Elmer's #50 completed
« Reply #4 on: November 20, 2017, 02:55:10 AM »
That's a nice action to watch Stan. Elmer, in his write-up, mentions that this engine represents the type of action a paddle wheel river boat would use. I can see that.

Jim
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Offline sshire

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Re: Elmer's #50 completed
« Reply #5 on: November 20, 2017, 04:31:52 AM »
I think Elmer was a more innovative designer than he gets credit for being.
The range from easy, beginner engines to some fascinating builds. Look at the twin pumping engine.
Best,
Stan

Offline AOG

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Re: Elmer's #50 completed
« Reply #6 on: November 20, 2017, 05:25:13 AM »
Probably because his more complex engines get built less. Take the number 50 you just finished, how many of those have you seen other than the 2-3 that have been made on this board. BTW good job on the cam. I think that the cam was the hardest part for me on this build. Yourís came out much nicer.

Tony

Offline sshire

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Re: Elmer's #50 completed
« Reply #7 on: November 20, 2017, 05:44:22 AM »
Tony
Agree. Iíve seen very few of the #17 Pumping Engine. I built it in 2013. A pretty challenging build.
Plenty of the simpler ones have been built.
I do think it would be helpful if the book were reprinted as the photos are quite helpful. Unfortunately, theyíre reproduced in a nearly unusable state. The photos of the cam operation in #50 on the John-Tom site are unrecognizable. Iím fortunate to have access to Fredís book. Just have to walk over to his house.
That said, if the plans werenít on the site, I canít imagine that any would have been built.
I was originally going to make the cam on the rotary table but, when I started calculating the setups and had already done the CAD, the CNC was the easier choice.
I did have one ďglitch.Ē Looking through the stock of cold rolled I was amazed to find that I had a piece of squarebar that was just what I needed, .75x.75.
Once I started the roughing cycle, I was constantly fiddling with the speed and feed controls. Just not cutting well. I unwrapped a new rougher which made no difference. Finally had the feed way down (IIRC 4 IPM).
It did get done. Not the best surface finish but the Scotchbrite wheel fixed that.
I was thinking about what could have made the milling so difficult as I never have an issue with CRS.
For some reason, I put a magnet on the finished cam. How that piece of stainless got into the stock box is beyond me. I donít ever remember buying stainless squarebar.
« Last Edit: November 20, 2017, 05:55:08 AM by sshire »
Best,
Stan