Author Topic: J Sisson 1945 Thompson  (Read 2196 times)

Offline 410Express

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J Sisson 1945 Thompson
« on: May 17, 2020, 01:23:48 AM »
Hello!
    I'm looking for drawings for the J Sisson version of the 1945 Thompson engine. I have Bob Herders drawings for his version, but the Sisson is a little different. Any help would be appreciated.
Bill Shamblin
Everything we do alters the future.

Offline Jasonb

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Re: J Sisson 1945 Thompson
« Reply #1 on: May 17, 2020, 08:20:24 AM »
Welcome to the forum, sorry but I can't help with teh drawings.

How did I miss this engine? I think it will have to go onto the to do list near the top though I'm not sure if Bob is still producing, any of our US members know the situation.

Looks like it could be fabricated or I could sit back and twiddle my thumbs while the CNC does the frame/cylinder "casting" from solid. Do you have any photos of the Sisson version or the full size as I could not see much on the net?

J

Offline michaelr

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Re: J Sisson 1945 Thompson
« Reply #2 on: May 17, 2020, 09:22:56 AM »
Hi Jason.
You may have found this site http://www.floridaame.org/ in the site click on Gallery then Single Cylinder Vertical engines and look for Bob Verhaeghe in the pictures, he has a picture of the John Sisson engine it also has a link to pictures of the castings and parts which may give you some ideas.

Michaelr
« Last Edit: May 17, 2020, 09:37:48 AM by michaelr »

Offline Jasonb

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Re: J Sisson 1945 Thompson
« Reply #3 on: May 17, 2020, 10:18:27 AM »
Thank's for that Michael, I don't visit tat site a soften as I use to but can see the differences between the Sisson and herder designs now with the frame of the Sisson being a bit "boxier" which would actually be more suitable for fabrication though I prefer the more flowing Herder design..

Bob Herders site has several photos too though I never like visiting as it always has my security program going nuts. Also found an old e-bay listing for one claiming to be an original but it look like Bob herder's not the Sisson. I wonder which is the original model from Thompson and if one of them was using the original patterns or both just made a version of it?

https://www.ebay.com/itm/VINTAGE-c1945-1-4-SCALE-AIR-COOLED-THOMPSON-GAS-ENGINE-MODEL-GRAND-RAPIDS-MI-/303523868693?nma=true&si=zHxklNW0uS9MreqILcFSqbNlA50%253D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557

There is also one on Youtube with the crank cover removed which adds a bit more interest visually.

<a href="https://www.youtube.com/watch?v=r-tBIqpZ0C4" target="_blank">http://www.youtube.com/watch?v=r-tBIqpZ0C4</a>

Offline 410Express

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Re: J Sisson 1945 Thompson
« Reply #4 on: May 17, 2020, 02:26:56 PM »
Thanks guys!   
    Bob Verhague's version does look a lot more like the castings that I have. And now I have a little more history about the prototype, as well.  :D
Everything we do alters the future.

Offline 410Express

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Re: J Sisson 1945 Thompson
« Reply #5 on: May 17, 2020, 07:02:22 PM »
These are my J Sisson castings.
Everything we do alters the future.

Offline Jasonb

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Re: J Sisson 1945 Thompson
« Reply #6 on: May 23, 2020, 06:56:12 PM »
I've been having a bit of a doodle to see if one could be made without castings and it looks like it should not be too hard. I've just based it on the photos I've found on the net and the couple of sizes given on Bob Herder's site and added a few features of my own. Dropped it down to 24mm bore x 24mm Stroke and a 100mm flywheel. Still needs some refinement but am pleased with how it is looking so far. I have wanted to do a Kawasaki green engine for a while and think this one will suit it, makes a change from red anyway!

Offline Jasonb

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Re: J Sisson 1945 Thompson
« Reply #7 on: June 12, 2020, 04:43:38 PM »
The complicated bit is now done and all the gears turn freely, should be straight forward work from now on.


Offline Art K

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Re: J Sisson 1945 Thompson
« Reply #8 on: June 12, 2020, 11:41:30 PM »
Jason,
This looks like a fun project.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Dave Otto

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Re: J Sisson 1945 Thompson
« Reply #9 on: June 13, 2020, 01:20:54 AM »
You have been busy, looks great!

Dave

Offline Jasonb

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Re: J Sisson 1945 Thompson
« Reply #10 on: June 13, 2020, 08:48:20 AM »
Thanks chaps, It's looking a bit better now as all the external corners have been rounded over, will leave adding the internal fillets with bondo until after it has been test run.

The socket  for the top gear's spigot had to be fitted prior soldering and the crank and can shafts drilled and reamed from the curved side of the frame so I was a little worried about getting the hole PCDs correct should anything have wandered but turned out Ok. In case you are wondering whet the top gear does I've added a bit of interest to mine.


 

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