Useful blade angle trick

[Stock Pot]

Here is a way to get the correct angle when sharpening a knife.

Measure the width of the blade at the handle end. Do this in millimeters, if possible (makes the math easier).

For 20 degrees, divide by 3
For 15 degrees, divide by 4.

That is the height you should hold the back edge, at the handle end, above the stone to get the desired angle.

A new, unshuffled , deck of Bicycle playing cards has 3.5. cards per millimeter. Do the math and count out the number of cards to get the height.

[taxlady]

Nifty

[justplainbill]

As a rule of thumb for a 25mm wide blade, I try to keep the spine 7mm above the stone; using a proportionately lower / higher height for narrower / wider blades.