[thefro526]

Originally Posted by DonRotolo

Agreed, either is fine, but by tapping the threads you get better threads and holding power, and gain re-usability well in excess of what self-tapping screws can provide. Plus machine screws have a wider variety of head profile available.

Tapping in delrin is easy.

What Don and Chris both said. Don's post also reminded me of my love for Delrin, it's so nice to work with.

Back on topic though, should you ever see or feel the need, you can also look into installing threaded inserts into the wheel, either a knurled press in type insert or a riv-nut should work pretty well. Only way I can see you having issues with threading right into the delrin wheel is if you have to change tread frequently and use a drill. If you don't start the threads by had (always start the threads by had) you could risk damaging/destroying the treads.