On 2010-02-04, Joseph Gwinn wrote:
In article ,
Ignoramus25542 wrote:

The cleanup of the lathe is basically done all around, the VFD is
wired the way I want and things are cookin'.

Got something else going on...

If I try threading, the half nuts would not stay engaged, they lose
this engamenent in a second or so. If I hold the engagement lever,
they they do stay engaged, but I feel the lever kind of bumping.

What would be the typical cause of this?

Wear and/or maladjustment. How much backlash does the closed half-nut
have? (This ordinarily does not matter unless one is making very
accurate and long screw threads, but is used to gauge wear.)

Joe... Thanks... I called Clausing and talked to Tito. He told me to
first clean the leadscrew very well and check the wear on slots of the
round slotted circle that closes half nuts.

This leadscrew proved exceptionally difficult to clean, in fact, I may
just take it off and use a powerwasher or take it to a hot shower. I
spent a lot of time cleaning it and it is still not as clean as it
should be.

The half nuts are $100 from Clausing, so even if they are bad, it is
not the end of the world.

i