Yep I suspect something like that will work a lot better than the standard 2 flute HSS slot drills I've tried. Not sure about the feeds for the 3.175 cutters but if I recall correctly I got ok'ish results in HDPE with something like 12,000rpm 2000mm/min and 2mm DOC and sprayed with WD40 with the cheap 6mm cutters. I stuffed around with a piece of acetal at some stage and from my little experience it cuts a lot easier and neater than nylon. I think acetal might be the same as delrin but don't take my word for it.