[tvdbon]

For my drive nuts I basically took a little nylon piece. Drilled a 5mm hole into it and then tapped it for 6mm thread. I use a 6mm think threaded rod with it. How easy should it be to turn the threaded rod ? My motors can turn it, but if I remove the motor from the rod and try to turn it by hand then it takes alot of effort to even move it a little. Is this right or should I be able to move it with my hand ?

[neilw20]

Welcome to the wonderful world of nylon.
When ever you machine it it spring away from the cutting face.

You turn it, and it will cut oversize.
You drill it and it will drill undersize.

If you need a thin wall and have turned the OD, it will drill heaps under as the outside surface weaves with the shape of the drill.

OK Drill it first.
The you turn the OD and it just pushes away from the tool.

One solution:
1). Make a metal bung the same size as the hole you are going to use.
2). Drill the hole in the nylon.
3). Push in the bung and hold with tailstock.
4). Machine the OD
5). Part off to finished length
6). Try to tremove the bung, without damaging the new part.
7). Make a tool to remove it.
8). Measure it. Damn. Wrong size.

Compensate, and start again!

[randyf1965]

When I made my first AB nuts I used part of a cutting board (possibly HDPE). Toss the part in the freezer over night then retap it while it is still cold

[mxtras]

Randy is spot on. Freezing the material prior to tapping will help.

Scott

[neilw20]

Good one. I had forgotten that one. (nuts)(chair)

[tvdbon]

Sounds interesting, I'll give it a shot. Thanks

[stepinator]

Don't forget the other old trick for Nylon and backlash. If you do get the threads cut and they are a little loose or starting to wear, make 2 nuts that can be fastened together, but before you tighten them togehter slip a shim cut from a pop can in between. Fasten and test, add more if necessary. Aluminum shims from pop-cans can used all over the place for trueing, leveling and adjusting all sorts of things.

.02$