9x20 Lathe Half nut ajustement trouble

[phelop]

Hi,

I replace my half nut on my 9x20 lathe (simiar to grizzly G-4000, Enco ) because all the thread are stripped. I install the new on and after mounting all parts, the half nut is not engaging correctly. When I close the lever, the half nut clip on the leadscrew and push it toward the lathe and don't keep on the leadscrew ( I need to keep pressure on the lever) . I don't figure how to ajuste this ? The leadscrew seem to be straight and I don't have any ajustement back and forth.

Regards

Philippe

 

[savarin]

There are a lot of variables to track down to get all this aligned to work as it should.
Have a read of this thread and see it it helps.

Stripped Half Nuts

well, not both halves. I cleaned the lathe the other day and made some adjustments oiled etc. When running the lead screw from the tail stock to the head stock with the half nuts closed as if threading I noticed the carriage stopped moving about half way along. It looked as if the half nuts had...

www.hobby-machinist.com

Also when re-assembling I found that loosening the apron screws, removing the screws at the tail stock end of the lead screw, engaging the half nuts with the saddle at the chuck end and you could watch the tailstock end of the lead screw come into alignment.
Tightened the apron screws, disengage the half nuts, run the saddle to the tail stock end, loosen the leadscrew screws again and engage the half nuts and see if the leadscrew moves, I am assuming the leadscrew is not bent.
Also I took a fine stone and using an edge of it I stoned the absolute edge of the threads to remove the very sharp edges.

 

[epanzella]

On my lathe (Grizzly G4003G) there is a vertical adjustment for the height of the halfnuts so they line up with the leadscrew. The whole halfnut assembly slides up and down in a dovetail. Get this adjustment wrong and they won't stay closed.

 

[phelop]

Ok ! I don't have this on my lathe....