@George_Allen acme and HDPE I made my own tap. So I just cut a thicker piece of plastic to make a longer nut and I don’t run that fast now. I keep it below 1,000 RPM. But it is good to see what you machine can take. I was just getting carried away trialling it. Look at how fast it can go. Whee!
@Paul_Frederick I bought some Delrin about a year ago to make a copy of the nut from open builds. I made an exact copy of it externally, using my 3020 machine, but I couldn’t cut the internal threads just right, so I didn’t bother with it further. Interestingly, I made a copy of it from PLA off of my Prusa printer with the threads already inside and it fit perfectly on a screw with the same TPI I bought from Lowe’s. Though, PLA is obviously not ideal for that application, it might have worked with nylon. I think you can even buy Delrin type filament. That stuff is hard as a rock! I got some stuck in a hole saw and I couldn’t even hammer it out. In retrospect I should have melted it out with a heat gun. Anyway, thanks for the help. I’m going to try to get some sleep for church tomorrow. I’ll keep you updated next week and see if I can get this train moving. Talk with you next week!
@George_Allen the beauty of plastic nuts is they are elastic. So that means they’re a little stretchy. It also means they’re zero backlash. But being elastic I had some trouble cutting threads in them. The resulting nut would be too tight. I would run my tap made out of threaded rod over and over through the nuts I was tapping and it was too tight. Because I needed rod a little bigger to cut the right size thread in the stretchy plastic. Then I came on the solution. I stretched the metal in the tap. Here’s a picture of how I did that. http://i.imgur.com/qNzAo9S.jpg
