was parting off a .75 inch did. aluminum piece. i kept having an issue of ships welding onto the HSS blade, so i kept retracting it and clearing the chips off. it started welding on chips, i presume, and i began to retract it. im guessing more and more welded on until it seized up in the groove and shattered the blade into three pieces. scary! luckily everything is ok except the cutoff blade. the blade was not even making a cut when it seized up. am i sharpening it wrong or something? it was running at a nice slow speed. to grind my parting tool (which has a T shaped cross section, are those P type or something?) i grind only the front face to give it some relief. i also grind it so that it leaves a clean face on the piece i part off, so it has end relief combined with a slight angle. i leave the top alone, becuase it has a little groove that seems to help the chip come out if the cut, but i guess it doesn't work effectively. any tips? this only seemed to happen on aluminum. no chip welding with brass or steel.