Since you seem to have some difficulty grasping the subject of this thread, let me remind you once again that we are talking about adapter sleeves/bushings for pen mills and not clock gears or propeller bearings or the price of tea in China. Even if we accept your premise that Corian is full of nasty abrasive, so what??? In the situation that started this thread, the bushing would be inserted into the 10mm brass tube of a blank and remain stationary while the pilot reamer of the pen mill turned in the 7mm brass tube inside the Corian bushing. Absolutely no way that the Corian, even if it were abrasive, could do any damage to a pen in the stage of being crafted or to the pen mill, itself. As to your comments about my crafting background and "trolling," it has been my experience that when a poster starts commenting about personalities rather than substance, it's because you...oops...he has run out of intelligent comments.
Eaglesc, if you feel the need to have the last word, go for it!! I've said all that I need to say on this particular topic.