Sending jointer knives out for sharpening is inconvenient and the results are not always great. Also, re-setting the new knives in the jointer is a time-consuming and tedious job. So Hendrik Varju came up with a way to sharpen jointer knives without removing them from the cutterhead. A simple locking jig and his easy to understand instructions are all you need.

From Fine Woodworking #224