Initially, the nozzle perfectly cut Walnut, Wenge, Purple Heart and Whig Chakta. After about 30 minutes of operation, however, the upper bearing appears to have collapsed. I don't know what happened but the set screw was tight and the second bearing seemed very stable. I've only ordered it again because there aren't many 3/8 top stock bits, but the delay will end up costing me a few hundred dollars in work.