If you are having trouble with your metal rule sliding off your sharpening stone while honing a blade, use a strong magnet to hold the whole piece together.
David Charlesworth developed a technique for forming a microbevel on the back of a plane iron when sharpening it on a stone. He uses a thin metal rule as a spacer under the blade. Trouble is, the rule tends to slide off the stone as you move the blade over it. To remedy the problem, I attach a strong magnet to the plane blade, which also holds my rule in place. Now I can take full advantage of this clever sharpening technique.
