Quote Originally Posted by Tom J View Post
I follow 50%+ rule of DOC which was 2mm in for 1/8" will try less. Going to buy decent Trend bit 1/4" 6.35mm
Cut some 4mm acrylic today using a 4mm shank/3 mm dia cut single-flute shop-apt bit. Did two passes @ just under 2mm on each with a finish pass. Feed rate 1200 mm/min with spindle speed around 13200 rpm (220 hz). Cut fine leaving a nice finish (just a couple of tool marks on one side.) Not saying that's the correct or optimal speed, but it worked for me. Usually I stick to smaller passes because I have a habit of not properly sticking/securing the acrylic to the spoil; and there's nothing worse than spending ages engraving acrylic just to have it lift from the table when cutting :)