Exactly.Loren wrote:Bore the inner diameter first, while the material is thick enough to resist flexing, don't over tighten the chuck or collet, and don't take big cuts.
Then, mount the piece on a mandrel to turn down the exterior to spec.
"Hairy when abraded", what exactly are you doing and how, when this occurs?
OP-- how are you turning your polymer? A machine lathe as opposed to a wood lathe I'd imagine.
I've found that Delrin or Acetal turns best with a very sharp lathe tool and taking very small cuts, especially as you approach the final outside diameter. It's definitely tricky stuff, but it makes a terrific whistle.
These polymers don't respond well to sanding, which is what I think you mean by "hairy". The sandpaper pulls up very tiny threads of the stuff but they don't fly off, remaining attached to the piece. You can sand it WET using automotive wet/dry sandpaper in the 400 grit and up. Keep it very wet. If anyone knows a good way to buff it, post it here.