Paul wrote:
I've got a Grizzly 9 x 20 lathe and need to cut some threads at 4 tpi. Any
thread charts for this lathe I've got only go down to 6 tpi. Question is,
can I cut 4 tpi on this lathe? And what gears do I use? Has anyone done
this? FWIW, when cutting coarse threads I use a hand crank to turn the
spindle.
TIA,
Paul



One way to do it is to get a set of gears that will give you a 1:2 ratio
and put them into the geartrain for the feed. Run the thread pitch
setting on the lathe at 8 tpi. I don't know what gears you have to work
with but you could also decrease the diameter of a driven gear by 2 or
increase the diameter of a driving gear by 2 and get the same result.

John