In article ,
says...
Eric R Snow wrote:
On Thu, 27 Oct 2005 20:23:48 GMT, Jim Flanagan
wrote:


Hello..
I wanted to ask anyone if they have attempted to do this on their
lathe. I only have a metal lathe and want to cut a flat archimedes
spiral onto a 1/8" thick piece of lucite. The spiral, fairly coarse,
would be something on the order of 6 turns/inch. The diameter of the
plastic would be about 3.5".

In any case, I could use some pointers as to how and efficently
accomplish this. Thanks for any advice you may offer.

-jim

It sounds like you want to cut a spiral on the face of a disc. Others
have responded with methods for cutting the OD of the part which would
give you a helix. If you are needing to cut a spiral then a manual
lathe isn't the best way for this because they are set up for
threading parallel with the Z axis, not the X axis. I have cut scrolls
Most newer lathes have "power crossfeed". As well as the half nuts
on the leadscrew for threading (Z axis), they have a keyway in the
leadscrew that drives a power take-off arrangement that turns the
crossfeed (X axis).

But in order to cut the approx 6 TPI spiral the feed would
have to much coarser than what's available on small lathes.

Ned Simmons