Finger Engine - my first build

piper184 · Jan 15, 2025

The first plan was to make a wobbler, but then I saw the plans for a finger engine and figured it would be a better first project. The finger tab looks much easier to make than a cylinder and piston.

It is done enough to assemble on a temporary base to work out any fine tuning. I have a piece of hardwood picked out for the base and am finishing it as I work on the last little details of the engine. It was fun and educational and I got to use the new DRO setup on the mill. I must say that the 1/2 function and the bolt circle function are my two favorite "tricks".

"Tricks are for Kids". Well, I'm still a kid at heart, so there's that....

cheepo45 · Jan 15, 2025

Very Nice! Great first project.
Scott

trlvn · Jan 16, 2025

Looking good! Did you follow one of the plans out there (which one?) or is it your own design?

Craig

piper184 · Jan 16, 2025

It was from plans by Kaje that I found on this site, which is a modified version of the NAMES plans.

The plans are nice and clean and easy to follow. The only issue I had is what I think is an error in the notes for the finger pad. It calls for a depression 0.150" deep in .25" stock, but then the holes from the bottom are 0.185" deep which resulted in a breakthrough. I remade the part from thicker stock but after assembly I think the depression is too deep to be comfortable. Perhaps it should have been 0.050". The current plan is to take it off and mill the top edge down until I like the feel of it a little better.

The only real change I made was how the crank connects to the shaft. I didn't have the set screw size called for, and I didn't have a tap for the set screws in my stockpile. Grrr! BUT I had a bag of 3/0 taper pins and a reamer for them, so changed to a taper pin. My pins were short enough that reaming the depth carefully I was able to "bury" the pin totally inside the crank out of view. It makes a secure connection but comes apart easily.

There are some small errors (mine) that you could find with a calipers or a careful eye, but for the most part it looks proper.