Ahhhhhh - that good ol' semi-solid uniaxially oriented fluoropolymer we all know and love -Tetrafluorethylene or PTFE or Teflon
That $hit is like machining a soft bar of Soap only much more abrasive!
I have to agree with the 'Mountie' there - depending on what you are trying to make, there are much better materials than pure Teflon usually available. Delrins or a filled Teflon like Vespel or the like would be much easier to machine.
Teflons have a low CF, but a very high Tg - which means they are as slippery as snot, but grow like crazy when heated! I use Teflons in my line of work because we need the absolute chemical resistance it offers, but it's a PITA at times.
Go get yourself a hunk and try to drill, tap and machine it. If the tolerances are off - just wait a couple hours, they'll change and you'll have to do everything over again.
The shops that work with this material alot usually 'anneal' it and then use tool wear compensating programs to machine it to hold tolerance. Of course Lazer Ablation is a promising looking option to get around the tool wear problems.
BTW - I'm not a machinist (but, I did stay at a Holiday Inn last month) just an old DuPont employee who got to meet Dr. Plunkett (Teflons Daddy) many years ago at a DuPont Function and has to deal with problems with the material daily.
Boy - now that was fun! [img]graemlins/clonk.gif[/img]