In article , Grant Erwin says...

You *are* using the half nuts and not the X powerfeed, right?

What grant said!

The ultimate tip-off in a questionable case like this is
to set the QC gearbox to thread the same pitch as the lathe's
leadscrew. Which in this case for a model A, I *think* is
8 tpi.

Then put a masking tape 'flag' on the leadscrew, and one on
the spindle as well.

If the geartrain is set up properly, when you turn the
spindle by hand, the spindle and leadscrew will turn
at the same speed.

If not then there's something out of kilter in the QC box
or on the banjo.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================