I'm trying to help a disabled fellow repair his electric powerlift on
his garden tractor. The motor gear is 32 pitch, 16 tooth, 0.58 face,
5/16 bore. I'm stuck on a couple of things. The bore is D shaped; the
motor shaft has a flat. There is no hub and no set screw. Gear is
sandwiched between the motor and an outboard pilot bearing in the
housing. I'm no machinist, so I'm looking for some direction here.
Maybe saw off a sliver of shaft and solder it in the bore?

Number two is how to determine the pressure angle of the teeth. 14.5°
or 20°. The gear is 27 years old if that is clue. Oh, did I mention
parts are no longer available.

There is a third problem. I have only the gear; not the motor. trial
fit is not possible.

I've found lots of sources but would welcome more.