[itsme]

Hi,

Getting the lathe spindle to index could be a bit of a challenge. I was thinking about maybe making a cutter (like an involute cutter) with the correctly shaped teeth for an internal gear. I would then use this cutter to make a broach, which would look similar to a spur gear, but have many steps getting larger on each step. Once this is done, I could then use some kind of press to press the broach through the hole and at the end of it, I should have an internal gear.

I don't think that the shape of an internal gear is the same as the 'negative' of a spur gear, otherwise I could just use a normal involute cutter to make the broach. On the other hand, I don't think the shape is that far off. I reckon a fairly accurate gear can be made at home, but I don't think it will ever be perfect.

Although the plans don't give much detail on the fixing of the spur gear, it does show the screw that is used. I think it is part 26. I've been looking at the plans, and still can't quite figure out why those screws aren't symmetrically placed. Is there something that I'm missing. It would just make sense to place them 90 degrees apart. I guess I can always make it up as I go along...as long as it works in the end.

Regards
Warren