Engraving and PCB Isolating Routing End Mill 60 Degree Tip - 1/8" Shank - Zrn Coated Made in USA

this is the best PCB mill I have used. I tried a large number of different bits and they did not cut thin enough or they broke all of the time. this set to 20,000rpm, 0.15mm depth, 250mm/min feed, and .3mm diameter cut a board that took about 25min of continuous cutting. no breaking and it stayed sharp.