I help coach the MIT collegiate pistol team, but end up spending half my
time doing gunsmithing. We have a whole raft of match CO2 pistols that
need occasional O-ring replacements, and I'd like to make a custom bench
block to hold some assemblies while I work on them. I have a couple of
general purpose commercial blocks, and I _think_ they are made out of
Nylon.

I'd like something easy to machine, but tough enough to put up with some
pounding. A couple operations require pressing very large snap rings
on/off or pounding out cross pins with the piece supported mostly on a
coarse sharp threaded section. I don't want the block getting chewed up
too quickly from those operations. I have thick blocks of PVC, but I
think that is too soft.

Likely suspects would be Nylon (several flavors), Delrin, or UHMW
polyethylene. Extra points for something I can get easily from McMaster
Carr in ~ 1.5" x 3" cross-section. They indicate that polyethylene has
better impact strength than Nylon or Delrin, but I'm not sure that is the
best metric.

Comments? Suggestions?

Thanks!

Doug White