Out of curiosity and a recent discussion with a customer prompted me to perform an unscientific experiment to provide a ‘meter’ for tweaking edge geometry. I think many are over thinking how much is really involved with removing 1° of edge material. It is in fact, fast and easy because little material removal is involved. Hopefully, this will help people to get less concerned about obsessing over angles and experiment on your own.
The conventional wisdom for setting or adjusting edge geometry is to use a progression of files, before changing to stones or diamonds for final polishing and honing. Depending on coarseness, files take off more material, much faster than stones or diamonds. This can be advantageous on one hand while a problem for some on the other hand for the same reasons.
Diamonds are far more forgiving and less intimidating than a typical bastard file and a 100 grit diamond is considered a ‘cutting’ tool, much like a super fine file.
So….under super clean, ‘highly technical’ conditions, I went from a 3° to a 2° and back on all four edges using an Ice Cut bastard file, 2nd file and 100 grit SVST on different edges. After removing the side walls and marking the edges with a Sharpie and following all options with a 200x, 400x and 600x diamond, I generally found:
-Bastard file- one overlapping pass got me close, a second more than changed the angle. One overlapping pass, followed by a few passes with a 100x should be adequate.
-2nd Cut file-3 overlapping passes followed by a few overlapping passes with the 100x and the other diamonds.
-100x diamond-5 fast, overlapping up and downs (10 passes).
By the time you clean files and swap cutting tools, the options were in relatively the same neighborhood of a couple minutes. If the edges were more chewed up, the files would have been much faster. To assure minimal material material removal, use the 100x diamond. To make more than sure, use a bastard at least twice, possibly followed by a pass or two with a second and then diamonds.
Following is a rough video using a bastard file on one edge to adjust edge geometry and then a diamond to Change Edge Angles on the second edge:
(You may need to refresh your screen to view. Firefox seems to have trouble loading this video.)