Sharpening Work

Clamp the tool in the jig, rest the jig on the support bar, and measure from the near surface of the bar to the cutting edge. Enter that number as is: the 6 mm to the bar's centre is added automatically.

Shop tip: cut a notch of your favourite projection into a scrap block and set every tool against it. Same projection every time, no measuring.

Measure the closest distance between the bar's surface and the stone's surface, along the imaginary line from the bar toward the wheel's axle (the green dashed line in the picture). A caliper's depth rod works well, and a spacer block cut to the target size works even better at the machine.

Measure straight across the wheel with calipers. The wheel wears smaller with use and truing, so a remembered bar setting slowly drifts to a different angle as the stone shrinks. That drift is exactly what this calculator corrects for, so remeasure whenever you true the stone.

Colour the bevel with a felt marker, set the tool on the bar, and turn the wheel a little by hand with the machine off. Where the ink rubs off shows where the stone is cutting: rubbed only at the edge means the angle is too steep, only at the heel means too shallow, and evenly across the bevel means you're set right. Trust the marker over any calculator, including this one.

Camber (a slightly curved edge) comes from varying finger pressure across the edge while grinding, not from the bar setting. Flattening the back is a separate job for a flat stone: the jig and this calculator only handle the bevel side.