Delrin Lead nuts.

[artmin]

Good thought on the heating whilst in location, but I found that with my Nema 23s, the resistance was too great once the polymorph cooled. I had to slit them to reduce the friction. It was an easy job, about an hour all in. I doubt it would be a problem for larger motors though.

As for the backlash, the old nut was a rattley fit. Most of my work is cutting hard aluminium, clearing plateaus areas. What I noticed was as the cutter plunged in on Z, the head was being pushed up against the screw by the reaction to the plunge, and with no dwell time on Z down, the movement on X&Y was leaving a 0.1 ramp as the head slowly dropped down on the backlash whilst traversing. With the feedrate used the ramp was about 15mm long. It didn't look good after anodising.

All sorted now though

[artmin]

A wee update on the polymorph lead nut. Three years on and it is still in perfect condition and in daily use. No noticeable backlash at all (not measured, just feeling for it) and the aluminium machining shows it. Just a drop of oil daily