I tried cutting a 8 TPI thread using the 1 on the dial and got three
diferent start positions.
Just counted the threads and it 16 or nearlu 16 per inch

I have a JET 9x20 and I successfully threaded a new back plate on it for a
4-jaw chuck without any problems. The spindle is 1 1/2 x 8TPI.

Have you checked to be sure the gear on the end of the thread dial is snug
up against the lead screw? It could be skipping if it's loose.

Best Regards,
Keith Marshall


"I'm not grown up enough to be so old!"