Cleaning up my old lathe

[Rickabilly]

Many designs of slide lock, use a tapered bolt or sliding nut with a tapered side and a bronze follower that would pass through a hole in that "Gib" when the bolt rises via the action of the thread the tapered side forces a lateral movement in the bronze follower which then locks against the bed, might sound complex but is very effective and discrete so when you want something to look unmodified it's a good option.

My H/V mill uses a similar design on the universal table swivel and also on the some of the other minor sliding bits

Regards Rick