This nozzle is amazing. If you use it correctly you will have BEAUTIFUL cuts. If you cut too slowly, EVERY bit will overheat, char, dull, and/or break. Touch the attachment once you've finished slicing (and the machine is safely off) and it should be at room temperature or slightly warmer. If it's hot, you're doing it very wrong. When cutting, you should discard CHIPS, not sawdust. Chips remove heat from the drill. I've cut at 324 ipm and had great cuts from 57-260 to 3/4" MDO (MDF veneer on waterproof plywood), I'll try 360 ipm (depth of cut .195-.2, 18,000 rpm on Shopbot Buddy I tested 4.2 IPS 4.8 IPS and 5.4 IPS they were all smooth my next test will be 6.0 IPS I cut very slowly with one of these and it was so charred that I couldn't calibrate the Z because it was no longer conducting current.were a bit blurry even at low IPM of 300 but with the new attachment the cuts were nice again.I also used 57-240 for test cuts and it seemed also good, but the maximum depth of cut of 1/2 inch severely limited its usefulness for me.