On Sun, 13 Nov 2011 23:55:51 -0800 (PST), Searcher7
wrote:

I was wondering if it was common to use powered metalworking tools on
plastic.(Nylon, Delrin, ABS, UHMW, PVC, etc.).

I assume that as long as melting your way through the stock is not an
issue then it is ok.

But is it plausible to expect decent accuracy/tolerances this way?

Thanks.

Darren Harris
Staten Island, New York.
Greetings Darren,
I machine lots of plastics on machine tools made for metal. It's
important to keep the plastic cool. Acetal plastics (Delrin and
Acetron for example) will release formaldehyde gas when heated too
much. This gas is corrisive as well as stinky and poisonous. Acetron
can be knurled with standard bump knurls. It deforms remarkably well.
Different plastics require different coolants. Water for acrylics,
soluble oil for nylon, uhmw, acetal. The oil does stick to the
plastics but comes off with the proper soaps. Oil must be kept away
from acrylic. It will cause cracks. The cracks may not show for hours
or days, or maybe not until the plastic is stressed. Sharp positive
rake tools work best for most plastics. Nylon absorbs water so if it's
going to be used as a water lubricated bearing it should be roughed
and then soaked in water a couple days before finish machining.
ERic