Lathe Cross Slide Problem

[Sunset Machine]

Are we talking about backlash, or is the thing wandering around in its slideway? If the latter, remove the nut and blue things up a bit to see where it's bearing.

My Southbend's compound was curved like a bannana, convex side up. As it moved it became loose. Prussian Blue showed it was contacting at opposite ends. A scraper made from an old file fixed it nicely.