Tapped Nylon Spacers as Lead Screw Nuts

[cely]

Either. There are more off the shelf sizes that are round.

I can get 1/2" long, round spacers from 4-40 through 1/2-20 threads in 1/4" diameter for the small threads and 1/2" diameter for the large threads.

I would prefer to have tapped spacers made from pre-lubricated acetal, but can't find them.

I think that it would be a significant contribution....if we can find a good solution.

[BillTodd]

I used PTFE (teflon) + M8 stainless steel threaded rod on my little engraver, seems to work well.

BTW the brass nut was an attempt to remove backlash, but because the M8 thread is fairly long and tight it proved unnecessary. The PTFE nut itself threaded M12 and is mounted to the ally bracket with a nylon nut. A dab of loctite stops the whole thing spinning.

[cely]

Thanks for the example. I'm not quite sure how the M8 Teflon nut is fixed to the bracket with Loctite. I didn't think anything would stick to Teflon. Teflon must run almost frictionless. I have looked but not found any pre-tapped Teflon spacers.

I too have found that there is less backlash with longer nut/spacers. A long nut/spacer has a lot of surface area in contact with the allthread rod. The goal is to get lots of contact area at very light pressures.

When I tap my own spacers, the fit is quite tight after the first pass with the tap. Depending on the allthread that I am going to use, I get a good fit after the 2nd to 5th pass with the tap. That's a good way to custom fit a spacer to a particular piece of allthread....however, I'm looking to keep my labor to a minimum and to design a solution that works with any piece of allthread. Compression or split nut seems to be the answer.