I can pull on my lathe's cross slide and make it move a bit

[Wonderclam]

I can grab my cross slide and push/pull it and the DRO shows it moves around .120


I have a PM1127 lathe, and if I have to turn something down, I gotta grab the cross slide and pull it back because if I push it to the workpiece, it gets pushed back a little bit. If I pull back on the cross slide, the Y axis stays the same when I'm turning. If I don't, the tool pressure pushes the cross slide back and I know this because the DRO changes. Is it the gib that I gotta tighten or is it the backlash nut I gotta tighten a bit?

 

[BrentH]

That is the backlash

If you can adjust it, then that is what you need to do. A good setting is around 0.005" if there is no adjustment- either you have a loose part or a worn nut, feed screw or both. 0.120 is way out of spec. You should always take the back lash out of a cut by backing out the feed and then feeding in so screw is tight and not in between threads. make sure your compound is also set into the cut for the same reason

 

[GL]

Agree with BrentH. Back the cross slide out to a relatively unused part of the screw and recheck. Screw worn if it changes a lot. Go for nut adjustment if similar or in either case. But 0.120 is way out.

 

[Chipper5783]

A little bit of back lash is common. It has been present on machines for several hundred years. Managing backlash is a normal part of machining. Certainly there are machines with loaded ball screws that effectively have zero backlash (most CNC machines would) - they cost more.