On Sat, 08 Oct 2005 18:28:57 -0700, Jon Anderson
wrote:

Doing some new parts for a new customer. A few of his parts, he doesn't
have drawings for, as they are purchased from the manufacturer of the
equipment he buys, modifies, and resells.

I have two bushings to make out of plastic, he doesn't know exactly what
they are made of. I thought MDS until I compared a sample to the
bushing. MDS from McMaster at least, is a sort of gray color and quite
hard compared to the sample. Sample part is a very dark charcoal black,
and under a microscope it looks like microscopic pits tear out of the
material in machining. Also seems to have very minute reflective flakes
impregnated throughout. It feels like Teflon, and a trial part I made in
Teflon has the right "feel" on the mating shaft. Both materials seem to
be about the same hardness. I know about Delrin AF, and it's certainly
not that.

I've never seen a black Teflon before. Almost like graphite filled...
Ring any bells?

Thanks,

Jon

Jon,
Is it machined or molded? If molded, cut a small sliver and
burn it to see if it smells like candle wax. If so, it could be molded
UHMW from Diversified Plastics in Missoula, MT. They grind a variety
of UHMW products and mold into a variety of parts and look very much
like your description. Good luck.

Tom..............