Hi Deisel,

Yeah, the Z was definitely in a bit of a state - had to clamp one end of the screw in a vice and get a spanner around the flange of the nut to free it up..! What I thought was going to wind up unusable has actually been working fine ever since - well - it's not as smooth as it used to be, but accuracy remains good enough for my purposes. The click on the Y I'm assuming is the nut, but won't know for sure until I dismantle the stages and have a closer look. We'll see.

Cheers for the advice.

Wal.