13 years ago
In process of making a worm, for Dave Lammas' dividing head, which is to
be 6.369 tpi, on my Cummins 7x12 mini-lathe.
Gears as: A = 50, B = 30, C = 60, and D = 40 will give me 6.4 tpi with
the 16 tpi leadscrew. An error of 0.487%, which over the short length of
thread in the worm is acceptable.
Cutting tool = 0.48" tip width and in-feed depth = 0.108"
Right, start cutting; got about 1/2 the final depth and a nasty noise
accompanied by little bits of plastic gear teeth.
Now this was done under power to the leadscrew.
Will I have more success at cutting the worm (and less success at eating
plastic gears) if I put a handle in the mandrel and turn everything by
What sort of in-feed would you recommend at this stage? 1 thou., 2 thou.,
Also, can someone point me to a changegear calculator that works in linux?
Mike in BC