Shear sharpening?!?
- This topic has 9 replies, 4 voices, and was last updated 04/07/2018 at 6:46 pm by
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In your photos, it looks pretty much like the barber’s shears I usually do. If I understand you correctly, you’re looking for a convex edge, as opposed to a flat bevel edge. This can be done on the WEPS by following the procedure outlined by Clay in one of his videos here.
I did a convex edge on an old kitchen knife recently, just to test a new method I had been thinking about try on my Gen 3 Pro. I started the bevel as usual, working toward the establishment of an apex. Having done that, I switched to my 800 grit and moved the angle to the next lower detent. After about 5 or 10 light strokes, I dropped to the next lower detent, did 10 more, then dropped another detent step, did 10 more and repeated this until I was happy with the overall look. The number of strokes you take is dependent on the blade thickness. If you have a very thin blade, more than one or two strokes could wipe out the prior flat. Then I went back to the highest angle and restarted the sequence with my 1000-grit stones. I repeated it with my 1500-grit stones and my 6-micron film. The trick seemed to be a matter of not taking too many stroke at any particular stage, as you could create just another flat bevel.
Note that I described a procedure for putting a convex edge on a knife. When using the WE scissor attachment, you would start at a low angle and increase the angle with each step.
I only tried this once and it worked after a fashion. Being less than impressed with the results, I re-profiled to a standard bevel, but it looked to me to be another viable method of creating the convex edge. I think I’ll try it again on my Victorinox chef’s knife, which had something similar to a convex edge on it from the factory.
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Shawn, I wanted to chime in here because I am a shear sharpener. I bought a scissor adapter for another sharpener and the WE is really no different. I am optimistic on a lot of things sharpening and this idea is one I feel can only be adopted if you want mediocre results. I can sharpen a bevel edge scissor on my knife sharpener. It’s easy and any bevel would be. They turn out great. I bought one prior to starting business. The thing to consider here is the angles are flat not convexed. People talk about a convex edge in knives as having one or multiple angles outside of the finished angle, but in a convex scissor remember there is no straight bevel, but one curve. They are talking about adding micro-bevels and get closer to final apex. Microbevels on a convex shear are bad. The apex on a scissor is where those two edges meet in space along the line of the two blades coming together. That’s not such an issue for knives. If your apex is left or right of center not a big deal it can still be wicked sharp. The blade can be bent, and knife will still cut. Not in a straight line but it will cut. Consider the scissor has to be two blades in a line. I own a machine that costs thousands to do what you are asking. A convexing jig requires a rotational component to turn the scissor blade around a radial point to form that convex outside. My clamp jig holds each blade and once I have the angle set on the minimum rotational angle or what is the blade angle for the scissor I then rotate my wrist to follow that convex edge over to that stop I just set. IF I hold it there for any fraction too long bevels begin to form not good. For reference that last pic is what we are speaking of. Any stylist would consider that shear destroyed. It might be fixed by rolling back the beginning of the new convex edge to the leading-edge side of the bevel and rework it. I know a guy who fixed one like you have. Most won’t bother because the amount of metal removal required makes this shears blades so short the ability of the shear to cut might be compromised by lack of steel remaining for integrity. Essentially, I start off doing test scratches until I get the angle high enough to scratch right at the very edge of the blade. Too steep of an angle starting out to begin with and you destroy that beautiful beginning thin edge at worst ruining it (like yours) and never cutting with it and at best killed years of use from a good scissor. I get the idea of multiple small straight line passes at different angles to sharpen the blade, but the WE is first and foremost a knife sharpener. Used to create bevels of varying angles that meet at an apex. I can have a scissor torn apart sharpened, lubed and back together in under 15 minutes. If you did the technique as described above on a convex scissor blade you would have to set the angle, sharpen, change jig angle finite amount resharpen, over and over. I’m thinking hours of work. All the while hoping you never create a bevel on the leading front edge. The exact thing a WE is designed to do very easily!!!The other option rotate the jig in one hand and try and apply motion with the stone in the other which also defeats the main advantage of the WE (Freeing your hands up so run stones) The main advantage to a shear sharpening machine is clamping the blade and having the jig to hold the radius constraints for you. I am sharpening free hand with rotational limits on a flat abrasive disk. WE is a jig fixture designed to maintain the same bevel or angle. It’s what makes it work so well for knives, but don’t try that with a convex edge scissor. Convex scissors are so finite in their convex angle I literally have sharpened a blade that 1 degree more or less from ideal can be the difference between that scissor cutting like they should, or a stylist coming back to me and say redo it because it’s not cutting at all. Use the correct tool for the correct job. Shawn there are jigs out there, but they typically are the focal point of a machine made for doing exactly what you want. If you are looking for a project to fix that blade mount it like TC stated. Work from the front cutting edge and roll back till you reprofile that edge to look like the others. Obviously make sure the other blade is the same. I can’t imagine doing that myself on my WE, but if I had a few hours where I wanted to try I might attempt on one of my shears I use for demonstration.
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