Thompson Engine

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Dec 18, 2013
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I recently started to build a Thompson Single Cylinder Engine

The first operation was to machine the base flat

Thom Engine.jpeg

Thompson Engine - 1.jpeg

Next was to machine the bottom and the top of the cylinder flat and then bore out the casting for the steel liner

Thompson Engine - 2.jpegThompson Engine - 3.jpegThompson Engine - 4.jpegThompson Engine - 5.jpeg

Taping the holes out that fix cylinder to the base

Thompson Engine - 6.jpeg
 
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I don't know this engine, I am fairly new to model engineering, but that looks great! I love watching build threads, a chance to learn.
 
Turning the crankshaft
The crank for this engine was meant to be made in 3 pieces, but I decided to make it in one piece

first I turned the front end down to size, then I had no way to hold it in my 4 jaw chuck, the jaws couldn't close down far enough to hold it with the offset I had to have
So I then made a fixture to hold it in the 3 jaw chuck, using a piece of round aluminium I drill and reamed a hole to fit the shaft, I then cut a slot along the hole
The hole and the seat came out to be almost the same size, I pushed a small screwdriver into the slot and that allowed the shaft to slide in, taking the screwdriver out and it locked on to the shaft
This allowed me to turn the rest in the 3 jaw chuck, pressure from the chuck jaws also held the shaft solidThompson Engine - 18.jpegThompson Engine - 19.jpegThompson Engine - 20.jpegThompson Engine - 21.jpegThompson Engine - 23.jpeg
 

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    Thompson Engine - 22.jpeg
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Hi Michael, LOVE IT!
But just as an observer, and not really knowing how stiff the farme is, (it looks quite "flexible" for machining?) I would have put a support beneath the cylinder while you were skimming the top and drilling the bore? (first pic #2):
1681892186859.png


Anyhow, it looks like you managed a good job.
Wll done on an excellent and enjoyable log!
K2
 
Hi Michael, LOVE IT!
But just as an observer, and not really knowing how stiff the farme is, (it looks quite "flexible" for machining?) I would have put a support beneath the cylinder while you were skimming the top and drilling the bore? (first pic #2):
View attachment 146163

Anyhow, it looks like you managed a good job.
Wll done on an excellent and enjoyable log!
K2
Hi K2

Thank you

Your probably right but it was very rigid though and only very light cuts

Michael
 

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