Half Nut Disengaging

[ddickey]

Threading yesterday on the lathe and my half nut opened twice, the last during a cut. I had to finish the threads holding the nut closed.
Is there a clutch type mechanism that disengages the nut due to excessive forces? Is there an adjustment somewhere?
Oh and I never disengage the nut, maybe I shouldn't be doing that.

 

[darkzero]

On my lathe there is an adjustment screw on the right side of the apron for the half nut. Have to remove the thread dial to access it. I've never needed to adjust mine but on my old mini lathe I had to adjust the detent for the handle as the lever started dropping randomly. I remember it also had a detent for keeping it in the down position.

Not sure if those 2 things are the cause of your issue but worth a try?

 

[benmychree]

could be excessive wear in the half nuts.

 

[savarin]

I had to drill the detents deeper on my 9x20 and up the spring pressure to hold my lever in place.