leadscrew nut re taper attachment

[TomG]

So hear's a hairbrain idea...

Make a nut to fit the cross slide screw and cut the thread at a 45º angle. Then cut a clearance hole for the screw at a 45º angle to the thread. Now when the nut is at 45º, the threads will engage and when it is rotated 45º, they will disengage. All you need then is a way to rotate and lock the nut to the two positions. That should be pretty straight forward because there is already a mounting screw and hole for the nut.

Tom