Knife sharpening terms
Knife sharpening terms
I can sharpen a knife, and do pretty well, make a blade hair splitting sharp, but I dont understand some of the terms, like an "Inclusive Angle" what does an inclusive angle entail? is that the main edge or a secondary edge?
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The Deacon
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Inclusive angle is the actual angle formed by the edge. As an example, in order to achieve a 30º inclusive angle, you'd normally sharpen at 15º per side, but a 30º inclusive chisel grind would be 30º on one side and 0º on the other. Sharpmaker rods can be positioned 15º or 20º off vertical to create 30º and 40º inclusive edge grinds, respectively.
Paul
My Personal Website ---- Beginners Guide to Spyderco Collecting ---- Spydiewiki
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WTC # 1458 - 1504 - 1508 - Never Forget, Never Forgive!
My Personal Website ---- Beginners Guide to Spyderco Collecting ---- Spydiewiki
Deplorable :p
WTC # 1458 - 1504 - 1508 - Never Forget, Never Forgive!
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jackknifeh
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Deacon covered the per side vs inclusive angle question.
The thing that can get confusing because of different words or terms to reference the same thing is the different parts of "the edge". In addition to "the edge" different people may use the same words to reference the blade shape or "grind". I'll devide the parts into sections and use the words I like. This will always be an issue it seems so sometimes we need to pay attention to the way the word is used to try to understand what the writer is talking about.
"The edge": I consider the edge to be the apex (very very edge) and also the bevel(s) created when sharpening.
"The grind": I consider this to be the rest of the blade. Normal words used are saber, hollow, full flat grind (FFG) and I'm sure there are others.
My preferred terms to talk about "the edge":
The edge bevel is the bevel that has "the very very edge" at the bottom of it. The very very edge is called the apex. Where the two side bevels meet.
Above the edge bevel is a back bevel. There may or may not be a back bevel or there can even be more than one. I put a 40 degree angle on the edge of an Endura once then created a 36 degree back bevel then 34, 32 and 30 degree back bevels. You need a sharpening system capable of about any angle to do this. It will create a "fake" convex (rounded) edge. A true convex bevel or edge is round from where it starts at the top of the sharpening area until the two sides meet at the apex. My EP (sharpening system) created multiple flat bevels instead of one continuous curved one. The back bevel is usually there just to thin the blade. A thinner blade always cuts or slices better and easier. Therefore the thinner the better for cutting performance. However the thinner the steel the more fragile it is. A knife needs to have a happy middle ground.
The words or terms used to describe the edge area were the most confusing to me and still can be. I adopted "edge bevel" and "back bevel" because I believe these are the terms Spyderco uses and they make perfect sense to me. A popular alternative set of words is primary and secondary. I would call the primary edge or bevel the cutting edge. The secondary bevel would be what I call the back bevel. But many people seem to use these words completely opposite than I would have thought.
Oh yeah, I forgot a major term. Micro bevel. A micro bevel is the edge bevel. I only call it a micro bevel when the edge bevel is VERY VERY small. Almost invisible to the naked eye. Once the micro bevel becomes easily visible to the naked eye I drop the word micro and use the word edge. One benifit of a micro bevel is to increase the strength of the edge and make touch ups quick and easy. Also, it is MUCH easier to get a hair whittling edge when the edge bevel is very small. Sharpening a wide single bevel into a super sharp edge requires more time. It also requires more skill IMO. I use a micro or edge bevel almost every time I profile a knife edge. If I do use just one angle 30 deg. inclusive (15 per side) for example it will stay that way until the first touch up. Then I'll put a micro bevel on it at a higher angle. After a few touch ups the micro bevel will become wider and I'll then call it the edge bevel because I don't consider it "micro" any more.
I hope this helps people. The terms I prefer are just that. My personal favorites. Not necessarilly the better choices. It is better when discussing something to use the same terminology but that doesn't happen often when people from all over the world are in the discussion.
Jack
The thing that can get confusing because of different words or terms to reference the same thing is the different parts of "the edge". In addition to "the edge" different people may use the same words to reference the blade shape or "grind". I'll devide the parts into sections and use the words I like. This will always be an issue it seems so sometimes we need to pay attention to the way the word is used to try to understand what the writer is talking about.
"The edge": I consider the edge to be the apex (very very edge) and also the bevel(s) created when sharpening.
"The grind": I consider this to be the rest of the blade. Normal words used are saber, hollow, full flat grind (FFG) and I'm sure there are others.
My preferred terms to talk about "the edge":
The edge bevel is the bevel that has "the very very edge" at the bottom of it. The very very edge is called the apex. Where the two side bevels meet.
Above the edge bevel is a back bevel. There may or may not be a back bevel or there can even be more than one. I put a 40 degree angle on the edge of an Endura once then created a 36 degree back bevel then 34, 32 and 30 degree back bevels. You need a sharpening system capable of about any angle to do this. It will create a "fake" convex (rounded) edge. A true convex bevel or edge is round from where it starts at the top of the sharpening area until the two sides meet at the apex. My EP (sharpening system) created multiple flat bevels instead of one continuous curved one. The back bevel is usually there just to thin the blade. A thinner blade always cuts or slices better and easier. Therefore the thinner the better for cutting performance. However the thinner the steel the more fragile it is. A knife needs to have a happy middle ground.
The words or terms used to describe the edge area were the most confusing to me and still can be. I adopted "edge bevel" and "back bevel" because I believe these are the terms Spyderco uses and they make perfect sense to me. A popular alternative set of words is primary and secondary. I would call the primary edge or bevel the cutting edge. The secondary bevel would be what I call the back bevel. But many people seem to use these words completely opposite than I would have thought.
Oh yeah, I forgot a major term. Micro bevel. A micro bevel is the edge bevel. I only call it a micro bevel when the edge bevel is VERY VERY small. Almost invisible to the naked eye. Once the micro bevel becomes easily visible to the naked eye I drop the word micro and use the word edge. One benifit of a micro bevel is to increase the strength of the edge and make touch ups quick and easy. Also, it is MUCH easier to get a hair whittling edge when the edge bevel is very small. Sharpening a wide single bevel into a super sharp edge requires more time. It also requires more skill IMO. I use a micro or edge bevel almost every time I profile a knife edge. If I do use just one angle 30 deg. inclusive (15 per side) for example it will stay that way until the first touch up. Then I'll put a micro bevel on it at a higher angle. After a few touch ups the micro bevel will become wider and I'll then call it the edge bevel because I don't consider it "micro" any more.
I hope this helps people. The terms I prefer are just that. My personal favorites. Not necessarilly the better choices. It is better when discussing something to use the same terminology but that doesn't happen often when people from all over the world are in the discussion.
Jack