"Michael Gray" wrote in message
news
I have a Cummins 7x12 minilathe and a nicely hand-ground Acme profile tool
I made. Right, so I have to cut a worm at 6.4 tpi. the change gears
with my 16 tpi leadscrew will be:

(30/50) x (40/60)

Can SKS tell me how to set this up so the gears actually mesh? Do I have
to somehow interpose an idler in there somewhere?

Help!
Mike in BC

Generally speaking you need to couple the 50 and the 40 together so they
rotate in unison. Not sure how you do that on a mini lathe. A 24 and a 60 in
the gear train give you the same ratio ( but I see from the grizzly web page
that that the 7x12 does/may not have a 24 tooth gear).

Carl Boyd