Belt sanders and steel: knives or razors
I attended a lecture by a metallurgist who works for Rolls Royce and he told us of their new equipment for measuring heat at the edge of steel. Heat treat temps are exceeded in less than a second at a thin edge like a knife or razor and it's not only the grinders. He said the worst offender was a buffing wheel (linen or cotton or paper) because no one thinks about them as heat generators. He only uses hand held hones now and he makes knives of unbelievable beauty and thinness and they hold their edge.
I like slurry honing because the slurry prevents any possibility of heat treat being lost. There was a posting on a knife forum about a guy who was using a spyderco v-stick so fast that a curl of hot metal flew off and landed in his eye. Not good and most unexpected using that tool! He must have been going really fast.
Sooooo... for razor honing and knife honing I use my Shaptons wet and my coticules with slurry. We work too hard, as bladesmiths, getting an edge to where we want it to ruin it with a belt grinder taking out the heat treat.
