When first sharpening my Sebenzas on a Sharpmaker I found that the belly and tip areas of the blade were not turning out as sharp as the straight blade section. This caused me to not only "oversharpen" the straight blade section but also widen the edge grind bevel while trying to reach the dull area of the belly and tip. What follows are ONLY MY OPINIONS and personal observations. This technique removes only a small amount of metal and prolongs the factory edge bevel by sharpening at close to the original grind angle. It sharpens relatively fast since the rods only contact the cutting edge and avoid abrading the sides of the grind bevel. This technique is NOT USEFULL for chip removal, edge reprofiling or sharpening at any angle that is not very close to the current edge bevel grind.
A Sebenza's factory edge grind ANGLE, although consistently well applied is not uniform throughout it's entire length. It is also slightly convex. On the knives I've sharpened, the factory edge grind angle from the choil to the beginning of the belly is at or near 20 degrees per side. This angle increases slightly from about the rear third of the belly to the front third of the belly and then decreases slightly from there to the tip. Therefore, when sharpening, if the contact angle of the blade edge to the Sharpmaker rod does not closely follow the factory applied angle changes, the metal removal may be spot on target in the rear portion of the blade but miss the cutting edge entirely in the curved areas of the front. Like bench stones, using the Sharpmaker is actually "free hand sharpening". The stone angle is fixed while the angle of the blade to stone contact is maintained or varied by the hand of the user. As with many ideas, the methods I use to address this combination of Sebenza and Sharpmaker are not original. They are a compilation of concepts and experience graciously shared by other. With a little repetition this technique quickly becomes ONE FLUID MOTION. It sounds difficult but in practice it is not. When the STANDARD Sharpmaker technique was first described to me as " hold and keep the knife blade horizontal, edge down, and while evenly pulling it toward yourself slowly slide it down the edge of the rod from top to bottom while maintaining even contact pressure between the knife edge and the rod surface ending with the knife tip against the rod at the completion of the motion" it sounded complicated. In practice it was not. Most Sharpmaker users have found that these multiple requirements quickly became one easy motion.
Here is the method I currently use on my Sebenzas:
**Use the Sharpmaker rods set at the 40 degree angle. Use the rod CORNERS ONLY. Mark entire edge bevel with marker. All sharpening is done by stroking toward you from choil to tip. Hold the blade edge parallel to the Sharpmaker base as usual. Perform three or four full strokes on each rod. Examine blade to determine EXACTLY where the rod corners are contacting the edge grind, ESPECIALLY on the REAR STRAIGHT SECTION of the blade. If the contact area has actually reached the edge along the ENTIRE blade length ~ refine it with higher grit rods, strop etc. and have a nice day. If the contact area is very close to the extreme edge (about 1/64") ~ along the rear straight blade section - good. If not, continue sharpening with the blade still held parallel to the base until it is. Don't worry about the belly section and tip just yet. Ideally the contact area should be close but not touch the very edge. 1.) Now, still holding the blade parallel to the base while pulling the knife toward you, AS the rod edge begins to contact the start of the the belly, slightly and smoothly RAISE the knife handle, carefully ending the stroke at the tip with the handle elevated. The concept is to keep the tiny blade edge to stone contact area as horizontal as possible as it moves along the curve of the belly.[[this keeps the edge bevel from widening]] 2.) Building upon this, ~WHILE stroking AND AS you raise the handle, slightly TILT the SPINE of the blade toward the opposite rod. This tilting will move the grind "SHOULDER" { I know it is actually slightly convexed } away from the rod allowing the rod corner to sharpen just the edge itself. [[this further reduces unsightly bevel widening]] 3.) Continue building upon this, ~ WHILE stroking AND raising AND tilting, SMOOTHLY MOVE the butt of the knife handle about one inch toward the opposite rod AS you pass the front of the belly section and proceed to the tip. This movement will help follow the changing edge angle and curve from the front of the belly to the tip. Keeping the blade edge to rod contact pressure consistent throughout the full length of the sharpening stroke will help avoid "oversharpening" in one area. The combined sharpening motion consists of three components: Stroke with edge parallel to the base while sharpening the straight blade section ~ elevate handle WHILE tilting spine inward as you move along the curved belly section ~ move knife butt toward opposite rod when passing the belly and on to the tip. With a little repetition it becomes ONE CONTINUOUS MOTION. Frequently re-mark and inspect the bevel to monitor your contact angle and progress as you now sharpen that last 1/64" of the edge. This technique just mimics the motions used when free hand sharpening on horizontally mounted bench stones with modifications made for the vertical orientation and different shape of the Sharpmaker rods. Go slowly and smoothly. Sharpening one edge until a burr is raised before switching sides or alternating rod to rod without a burr seems to yield the same result. The alternating rod method however removes less metal. The goal is to create a very large micro-bevel while following the factory grind angle changes. It also helps keep a cosmetically uniform edge bevel intact. Once you are satisfied with your technique and the initial results, you can refine and polish your work on the corners of a higher grit rod and or strop. Using the Sharpmaker flats inhibits the effectiveness of this technique since it relies on the narrow surface of the rod corners. The flats can eventually be used but it requires more practice and precision. There are undoubtedly other and more efficient methods of using a Sharpmaker while maintaining a Sebenz'a uniform edge grind width. But ... since my bench stone sharpening skills S*#K, this one works for me. And yes, I am this obsessive and boring in person. OldDude1
