On Oct 24, 10:30*am, Don Foreman
wrote:
On Fri, 24 Oct 2008 08:21:30 -0500, "Karl Townsend"

wrote:
I need to make some new idler wheels for my wire EDM. The material is a very
hard black plastic. Maybe the same stuff you see on a car electrical
distributor. It needs to be non-conductive and be able to have a light press
fit for a ball bearing.

Can somebody give me a material name and source to order?

Karl

The most economical way to produce things like this is to mold them.
However, that isn't necessarily the only way, nor the best way if you
don't happen to have the molds. *

I'd make an undersized aluminum wheel, press that into an insulating
bushing made of Delryn, Noryl, phenolic or whatever, and then possibly
press that assy into a metal "tire" that would resist wear. *The
resulting wheel would be non-conductive from rim to center and would
be quite robust.

What voltage?
Especially in a dusty environment, creepage may be as important as
clearance.
(Creepage is the distance of the path from a hot lead to another
conductive surface, along the surface of the insulator.)


Dave