Bill McKee wrote:

My Atlas 1/2nuts always are disconnecting from the drive screw. What should
I look at there?



First, clean the screw and nuts and associated mechanism. You may need
an awl or something to pick the most stubborn bits of swarf out of the
teeth. If the half nuts or the cam that engages them are badly worn,
there may not be much you can do to help them. If you have a 3/4"
leadscrew, replacement parts are available from the Clausing Service
Center for what seems a reasonable price. If the leadscrew is bent, it
need to be straightened. Also check that the leadscrew is running
through the center line of the nuts. if the bed has been ground or
something it might be off-center.

My recollection is now hazy, but I seem to recall a detent ball and
spring that helps retain the cam and engagement handle in position.
So you can check the condition of that.

If the teeth of the nuts are worn very much, they form a ramp that
drives the nuts apart. Also, a really badly worn leadscrew can get
the same way. The only hope there is replacement.

Jon