Just remember when grinding them to shape, not to let them get too hot, or you can draw the temper out of them, and re-tempering is a mystic art, practiced by secretive persons in leather aprons in dim caverns back in the hills.[/QUOTE]

As a person who has been involved in the metals industry for almost 35 years I can't stress how very true and important that statement is. The key is to take your time and grind small portions at a time. Don't press too hard against the grinding wheel trying to take off large amounts of material all at once. Slow and easy will allow the metal to retain its temper and thus its ability to take and hold an edge. If the metal loses its temper the edge will be quick to dull and the entire blade will be brittle.