I changed computers and so far the tool jerking in and out has disappeared. Thanks, I couldn't have done it without you guys. I only have so much hair--left.  Now I'm going to cut some threads on 3/4" pvc pipe for practice. Is there an acceleration number I shouldn't go under for any tpi and spindle rpm ratio. ie a formula?
Ben

Or does Mach use the acceleration listed in the "motor tuning" entries to calculate landing at the correct start point?
Ben

Have a look at the Threading On the Lathe Writeup in Members Docs.
 
Try scribing lines on somethng. Can be used over and over again.

Mach will use the values you provided in motor tuning. Acceleration from a stopped position to some point in a time period
can usualy be addressed by allowing 3 to 5 threads ( general rule of thumb) in distance prior to actualy cuttting the thread.

Try scribing different tpi and rpm and don't ignore the wizard warnings  if  you are exceeding your settings.

If scribing is of good quality then do some actual threading in different materials to gain experience on using your lathe.

You'll be a pro in no time at all.....
RICH

Thanks Rich and Hood you've both been a great help.
Ben

Glad we could help.
RICH