CJ,
Delrin (trade name) or acetal cuts like butter. It is harder than some plastics but to an end mill or drill bit it is a piece of cake.
It is more brittle than say HDPE or UHMW and not as "tough" as Nylon, (which sucks to cut as it wraps around every thing and doesn't form a good chip).
Torlon is quite abrasive, but that's another story.
