Wood,
Thank you sir. They did turn out ok , in a primitave sort of manner. Its what he wanted. As you say, cool grinding is making sure the blade does not lose its original heat treat by overheating the blade. Harry Morseth, the famous knifemaker, was well known for his knives which were made out of Scandinavian laminated steel and which he cool ground. Files are a royal pain in the butt to grind, because the are designed to resist what you're trying to do to them. Trying to grind them using worn belts is a waste of time. Use new belts. I started out using 40 grit blue zirconium on these and then went to 100 grit, then 80 grit ceramic and then to silicon carbide belts. They get dunked in cold water after each pass on the grinder. I grind barehanded anyway, so it's pretty easy for me to know when the blade is getting hot. Not uncommon for me to dunk my thumb in the water before the blade!! You have to keep from applying too much pressure and moving the blade too slowly at the same time. That's a sure way to "burn" it. As you grind,watch for "colour"to start appearing. If it does, let off on the pressure and move quicker. A blade can handle getting some "straw"colour on it, but anything more than that is too much. If it turns black in spots, you might as well throw it away.
Don't be in a hurry. It takes me much longer to grind a file, than say 154CM or D-2. tempering is done in my toaster oven. Since these blades were most likely W-2 steel, after reaching the proper colour at the 400 degree heat,which is "straw gold", they get dunked in a 170 degree can of brine. You make the brine by adding salt to the water until an egg will float. I use a candy thermometer to check the brine temperature. thats it. Files are good to learn on, plus they make great blades. Mine really hold an edge.
