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Is there a "standard" or recommended edge angle for folders? Where can I read more about this? I would like to know what is the difference between 15, 20, 25, etc. degress. Thanks.
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edge angles
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Ankerson
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20 per side is the best all around angle, leaves good support for harder cutting.
15 Per side is better for fine slicing, but the edge isn't supported as well for harder cutting.
I wouldn't go above 20 or 21.
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Thinner angles cut better, but get damaged easier. I've seen some knives with edge angles as low as 3 degrees per side. However, it was a dedicated kitchen knife used only on boneless meat and stiff vegetables. The more you limit the use of your blades, the better performance you can get in their chosen area. In other words, if you carry a three blade folder, you could set on blade at 10/side, one at 15/side and one at 20/side. The thinner ones get used for a more limited scope of work, but will do better in that scope than the thicker ones. I carried a Schrade stockman for a while and set the spey blade at 25/side for scraping and such, the clip blade was at 20/side for general use, and the sheepfoot was at 15/side for finer cutting. With different/harder steels I probably would have gone to 10/15/20, mabye thinner. My current trapper carry knife is set at 20/side on the spey blade and 12/side on the clip blade. At this point, each have small microbevels from touching up the edge.
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I don't believe you can be definitive on this as there is too much variation - thickness/profile/steel/heat-treat + intended use(s). Having a multiple bladed folder as suggested in some of the replies is a great option
One of the reasons why Opinel have a reputation for being such great slicers is the combination of thin blade and convex edge. I take a leaf from that book and usually convex or micro-convex the edge on all my EDC folders so the actual angle becomes kinda irrelevant. I strive for the finest convex edge that will hold reliably and this will vary markedly from knife to knife depending on the steel and heat treat.
One of the reasons why Opinel have a reputation for being such great slicers is the combination of thin blade and convex edge. I take a leaf from that book and usually convex or micro-convex the edge on all my EDC folders so the actual angle becomes kinda irrelevant. I strive for the finest convex edge that will hold reliably and this will vary markedly from knife to knife depending on the steel and heat treat.
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What he said.
Most western kitchen knives are set around 45 degree inclusive (22.5 per side). That's close enough to 20 degree per side. It's as obtuse as I'd get for any knife (machete & axe are different). It's strong enough for chopping action without excessive rolling or chipping even with cheap steel. Most pocket knives are set to this angle as well, primarily because it's the strongest angle to withstand abuse while still sharp enough for regular cutting.
The next angle is 30 degree inclusive (15 degree per side). A minority of pocket knives are sharpened to this angle from the factory. It's considerably sharper so it's great for slicing and whittling, especially when combined with hollow grind profile. However, it's less tolerant to twisting, prying and general abuse. Mid grade and "super" steels can handle this angle for general use without any problem. I personally reprofile & sharpen my pocket knives to this angle.
Less common is 20 degree inclusive (10 degree per side). Scandi ground and Japanese chisel ground knives are sharpened approximately to this angle. Needless to say it's really sharp, but you don't use these knives for prying. Scandi ground knives like Moras use this angle because it works real well in shaving, whittling, and carving wood. Japanese kitchen knives are used with slicing rather than chopping motion, and this allows for very smooth and precise cutting even with soft tissue like fish.
Most western kitchen knives are set around 45 degree inclusive (22.5 per side). That's close enough to 20 degree per side. It's as obtuse as I'd get for any knife (machete & axe are different). It's strong enough for chopping action without excessive rolling or chipping even with cheap steel. Most pocket knives are set to this angle as well, primarily because it's the strongest angle to withstand abuse while still sharp enough for regular cutting.
The next angle is 30 degree inclusive (15 degree per side). A minority of pocket knives are sharpened to this angle from the factory. It's considerably sharper so it's great for slicing and whittling, especially when combined with hollow grind profile. However, it's less tolerant to twisting, prying and general abuse. Mid grade and "super" steels can handle this angle for general use without any problem. I personally reprofile & sharpen my pocket knives to this angle.
Less common is 20 degree inclusive (10 degree per side). Scandi ground and Japanese chisel ground knives are sharpened approximately to this angle. Needless to say it's really sharp, but you don't use these knives for prying. Scandi ground knives like Moras use this angle because it works real well in shaving, whittling, and carving wood. Japanese kitchen knives are used with slicing rather than chopping motion, and this allows for very smooth and precise cutting even with soft tissue like fish.
10 per side for those in the upper echelon of sharpening.
5-8 per side if you're willing to grind off the edge bevel entirely, and have lost some of your marbles (I've sharpened several knives this way).
As far as I've seen the "standard" angle for knife edges is 25 degrees per side. Some knife companies like Benchmade grind to 20 per side, but for the moderately-priced knives that most people wind up with in their pockets the general recommendation is 25. You'll often see sharpening tools recommend this as the "proper angle", but there's really not a huge difference between 20 and 25 in performance, edge retention, or even in the actual angle. Personally I like the way John Juranitch puts it, that you don't want to go anything over 25 per side, and you want to go as low your knife will go without chipping or losing its edge for the specific tasks its being used for.
I generally just go for between 20-25 degrees on a knife that I don't need to be a terrific slicer and I don't want to sharpen a lot. A lot of 440 knives that are "beater" knives fall into this category. Really my choice in whether I'll go with 20 or 25 or anywhere in between has nothing to do with how much better either one performs, but more to do with how quickly I can grind one or the other. If I have a blade that's pretty thick behind the edge, I'll grind in a more obtuse angle so that I can get the edges to meet at the center with less grinding than if I wanted to go to a 20 degree angle, and generally if there is even any loss in performance its negligible.
In any case, you really don't want to get too caught up in the specific numbers. I mean, most of these angles are just general guidelines, because a 30 degree inclusive angle is really not consistently better than a 40 degree inclusive angle, and the actual difference in performance between 20 and 30 degrees is much less dramatic from knife to knife. The true goal is to find a balance between an angle that is acute enough to perform very well at the task you need, but also obtuse enough to hold an edge doing the task you need. Recommendations of various angles are nothing but simple guidelines on how to achieve that. Only problem is that guidelines change from steel to steel, blade to blade, grind to grind, so as often as it is discussed it winds up seemingly like some kind of theory instead of a guideline.
This is how I see it generally working out...
20-25* -- Used for jobs where abrasive material is being cut, or a lot of material, or just very hard stuff. Any kind of job where edge retention is crucial because maintenance of the edge will be cumbersome. Example: A fast-paced factory environment where volume and speed of cuts matters the most and the time needed to maintain an edge may not be available or will hinder production too much.
10-15* -- Used for jobs that may be a little less frequent, on material that might not be so abrasive or demanding, where the precision, control and ease of the cut are more important that edge longevity and light edge maintenance is easily administered. Example: A non-professional task such as packag opening , letter opening, hobbyist activities like woodworking or cutting, where a user is not hindered by using something like a stone to maintain their edge.
0-10* Used for jobs that require extreme precision, control and ease of cutting, or on materials that are very soft, small or delicate, and where edge maintenance is not only easily administered but a planned requirement. Example: A barber or chef who need to cut delicate material without disturbing other material around it, and plan on maintaining their edge with a steel or strop in order to maintain that edge.
In my mind though, it's a sliding scale depending on a few things like the steel, the hardness of the steel, the blade grind, and the geometry. So for example, if I wanted a blade to keep its cutting edge in our first example's circumstances, then I might grind a knife with 440 blade steel and a thin edge to 25 per side so that it's not in need of maintenance too soon. On the other hand, if I have a knife of similar geometry, but in a nicer steel like S30V or 154, then I might go to 15 per side, and if I had one of the new super-steels I might even go lower than that.
Of course not everyone does that just based on the steel, but it's a nice idea that demonstrates the idea at hand in the case that many people when they get an S30V or knife made of nicer steel, they will grind it to a more acute angle than some of their other knives with the thought being that it will have the same amount of edge retention as the other knife, but with more cutting performance because of the more acute angle.
I generally just go for between 20-25 degrees on a knife that I don't need to be a terrific slicer and I don't want to sharpen a lot. A lot of 440 knives that are "beater" knives fall into this category. Really my choice in whether I'll go with 20 or 25 or anywhere in between has nothing to do with how much better either one performs, but more to do with how quickly I can grind one or the other. If I have a blade that's pretty thick behind the edge, I'll grind in a more obtuse angle so that I can get the edges to meet at the center with less grinding than if I wanted to go to a 20 degree angle, and generally if there is even any loss in performance its negligible.
In any case, you really don't want to get too caught up in the specific numbers. I mean, most of these angles are just general guidelines, because a 30 degree inclusive angle is really not consistently better than a 40 degree inclusive angle, and the actual difference in performance between 20 and 30 degrees is much less dramatic from knife to knife. The true goal is to find a balance between an angle that is acute enough to perform very well at the task you need, but also obtuse enough to hold an edge doing the task you need. Recommendations of various angles are nothing but simple guidelines on how to achieve that. Only problem is that guidelines change from steel to steel, blade to blade, grind to grind, so as often as it is discussed it winds up seemingly like some kind of theory instead of a guideline.
This is how I see it generally working out...
20-25* -- Used for jobs where abrasive material is being cut, or a lot of material, or just very hard stuff. Any kind of job where edge retention is crucial because maintenance of the edge will be cumbersome. Example: A fast-paced factory environment where volume and speed of cuts matters the most and the time needed to maintain an edge may not be available or will hinder production too much.
10-15* -- Used for jobs that may be a little less frequent, on material that might not be so abrasive or demanding, where the precision, control and ease of the cut are more important that edge longevity and light edge maintenance is easily administered. Example: A non-professional task such as packag opening , letter opening, hobbyist activities like woodworking or cutting, where a user is not hindered by using something like a stone to maintain their edge.
0-10* Used for jobs that require extreme precision, control and ease of cutting, or on materials that are very soft, small or delicate, and where edge maintenance is not only easily administered but a planned requirement. Example: A barber or chef who need to cut delicate material without disturbing other material around it, and plan on maintaining their edge with a steel or strop in order to maintain that edge.
In my mind though, it's a sliding scale depending on a few things like the steel, the hardness of the steel, the blade grind, and the geometry. So for example, if I wanted a blade to keep its cutting edge in our first example's circumstances, then I might grind a knife with 440 blade steel and a thin edge to 25 per side so that it's not in need of maintenance too soon. On the other hand, if I have a knife of similar geometry, but in a nicer steel like S30V or 154, then I might go to 15 per side, and if I had one of the new super-steels I might even go lower than that.
Of course not everyone does that just based on the steel, but it's a nice idea that demonstrates the idea at hand in the case that many people when they get an S30V or knife made of nicer steel, they will grind it to a more acute angle than some of their other knives with the thought being that it will have the same amount of edge retention as the other knife, but with more cutting performance because of the more acute angle.
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Some good advice here so far. My default angle is 15/side for EDC, 10/side for kitchen knives with premium steel (VG-10). Some of my S90V EDC blades are also at 10/side but that's an exception to the rule. Type of steel and intended use are the two things to consider. If I was using my knives hard, 20/side or 15/side with a micro bevel of 20/side would be my choice.
I am able to quickly touch up or sharpen a knife so long term edge retention is not a big factor. The knife will wear faster but I make that up in numbers.
I am able to quickly touch up or sharpen a knife so long term edge retention is not a big factor. The knife will wear faster but I make that up in numbers.
Some good advice here so far. My default angle is 15/side for EDC, 10/side for kitchen knives with premium steel (VG-10). Some of my S90V EDC blades are also at 10/side but that's an exception to the rule. Type of steel and intended use are the two things to consider. If I was using my knives hard, 20/side or 15/side with a micro bevel of 20/side would be my choice.
I am able to quickly touch up or sharpen a knife so long term edge retention is not a big factor. The knife will wear faster but I make that up in numbers.
Well, I think one factor in edge retention that people don't think about that much is edge holding. A lot of people focus on wear resistance--i.e. the dulling of the edge on abrasive material. However, one thing that the angle of the knife will effect is how the edge holds its shape, and how and when it will deform. So for example, a lot of steel like S30V might have excellent wear resistance even at 20 degrees inclusive, but at that acute of an angle the steel is just not hard enough to resist significant edge rolling when coming into contact with hard or solid surfaces--on the obverse, harder steel at the same angle may chip more readily rather than roll or dent. For example, if you have an S30V blade at 30 degrees inclusive and you wind up making contact with a hard surface, it will still roll and or dent, but it may not be as serious as it could be if it was at 20 degrees inclusive. If you then have a knife with very hard steel like M4 or ZDP-189, you might find that instead of rolling or denting being the deformation characteristic, that chipping might be. Either way, having the angle too acute is more of a problem than the steel itself in either circumstance.
That's why I think considering edge holding when taking about the best angle for edge retention is important than wear resistance, because personally I think the angle effects the edge holding more than the wear resistance. I mean, for example, if you're forced to cut a wire with S30V at 30* inclusive the deformation will be small and easily managed, whereas if you cut it at 20* inclusive it will require more time to remove the deformation. Even if the deformation is the same size, you will need to remove more metal to get rid of it at a more acute angle; worse yet the deformation could be much larger, requiring that much more metal to be removed. With that in mind, if you have a knife at an angle too low and are frequently grinding deformations out, you might find the actual life span of that knife significantly reduced (or the edge behind the bevel getting too thick too quickly), whereas on the other hand sharpening just to address the effects of wear removes much less metal and isn't as much of an issue.
So on the one hand, a steel like S30V has better wear resistance, and can be ground down to a more acute angle to take advantage of that, giving the user nominal wear resistance but better performance with little extra maintenance ( if any ). On the other hand, the cost of maintenance could be too high if the edge is to acute that deformations have to be taken out too frequently or if the deformations themselves cause that much damage. Just to think of a real world example, a knife made of some super-steel may have great wear resistance profiled at 10* inclusive, and will cut like a dream. However, if you accidentally deform the edge it could be a huge deformation, and grinding out deformations removes much more metal than simply resharpening a worn blade. Then the more it happens, the thicker the blade gets, until you need to reprofile, and even doing this you'll wind up removing so much more metal than you'd need to that you'll grind that knife past its usefulness long before you would a knife you just have to rehone every once in a while.
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Kenny, no arguments from me on "edge holding," I just call it toughness. For 95% (or even less) of the knives out there, a very thin edge is not practical. And for something like S30V, I don't go below 30 degrees inclusive.
My 20 degrees kitchen knives rarely see bone and in our kitchen, it's mostly chopping/slicing tasks. And S90V is something quite special. It's tough even when thinly ground but I wouldn't try that with something else.
My 20 degrees kitchen knives rarely see bone and in our kitchen, it's mostly chopping/slicing tasks. And S90V is something quite special. It's tough even when thinly ground but I wouldn't try that with something else.
Ahh, okay, I thought toughness was more related to things like blade snapping. I still haven't quite caught on to the lingo knifenuts use, I've been kind of a hermit knifenut for years. I spend a large part of my day reading terminology and going, "OH, so that's what you call that."
In any case, I spend more time worrying about how tough an edge angle will be rather than how wear resistant it is because I tend to strop everyday purely out of boredom and the idea that a sharp knife stays sharp easier than it becomes sharp.
To me 30* inclusive is the sweet spot. It's acute enough that you see some real improvements in cutting capability, but it's also still tough enough not to deform too much, and not so acute that when it does deform it's a huge pain to get rid of that deformation.
One thing I've heard in terms of wear resistance when speaking about polished versus coarse finishes though is that the more pressure needed to cut the more quickly an edge will wear. Which makes me wonder, why wouldn't it be the same for edge angles? I would think so since the edges are basically the same size at the point where they meet, and so if one was under more pressure it should wear faster. I've never seen anyone else suggest this though, and I suspect that most of the pressure is bearing down on the bevels themselves rather than the edge.
There is a lot of terminology used for knives that is...unique. Words like toughness and strength, edge holding and wear resistance get used interchangably and they certainly don't mean the same thing.
There are quite a few members here who have found that thinner edges cut better, longer than thicker ones. Buck was able to show that geometry can trump steel by outdoing BG-42 with their 420HC using superior geometry in a CATRA edge holding test. I suspect it has to do with what you touched on w/r to less effort wearing the edge less. Also, thinner angled edges get thick more slowly than thicker ones (duh). This all assumes wear is the primary reason for dulling, which is often not the case.
There are quite a few members here who have found that thinner edges cut better, longer than thicker ones. Buck was able to show that geometry can trump steel by outdoing BG-42 with their 420HC using superior geometry in a CATRA edge holding test. I suspect it has to do with what you touched on w/r to less effort wearing the edge less. Also, thinner angled edges get thick more slowly than thicker ones (duh). This all assumes wear is the primary reason for dulling, which is often not the case.
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There is no standard. The angle should be made to meet the requirements of application and the steel from which the blade is made. Too acute and the edge fails. Too obtuse and you waste some of the edge holding ability of the steel. My advice is to start on the acute side at a point where the edge folds. Then make it more obtuse with subsequent sharpenings until the edge no longer fails. That's the correct angle for that application and that steel.
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Steel type, HT, and intended use are main factors, but I sharpen all my knives including new ones to achieve about 1/16 " of sharpened edge. That's my working edge and I keep both sides the same using my Lansky, even different angles per side sometimes.
It all depends on blade profile and thickness/thinness to within 1/16 " of the edge as what angle it comes out at. 20/side on my hollow grind small Sebenza to 30/side on a Strider PT CC I had. Both shaved skin, both had same look with 1/16 edge. Obviously one sliced better and the other was more suitable for tougher use.
IMO any sharpening beyond a max of 1/16 is reprofiling.
It all depends on blade profile and thickness/thinness to within 1/16 " of the edge as what angle it comes out at. 20/side on my hollow grind small Sebenza to 30/side on a Strider PT CC I had. Both shaved skin, both had same look with 1/16 edge. Obviously one sliced better and the other was more suitable for tougher use.
IMO any sharpening beyond a max of 1/16 is reprofiling.
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A big +1
20 will also hold an edge a tad longer than 15, given the same steel/knife.
Of my users, I have none below 15, and none above 20.
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All opinels i have did not even have an edge when i got them, most certainly not a convex one. They do get wicked sharp however. But that can also be because of the thinnes of the blade..
:thumbup: well said
That's what the pros do
You might also want to read this for some more background info on stuff that kennyb says: http://www.bladeforums.com/forums/showthread.php?t=368828
As far as I know there are three characteristics of edge holding.
1. Resistance to deformation.
(Hardness)
2. Resistance to abrasion.
(Wear resistance)
3. Plasticity.
(Fracture resistance)
Note that some attributes will affect others. Harder metal will also be more wear resistant, and will roll less, but may just chip instead.
Toughness is the combination of hardness and fracture resistance.
1. Resistance to deformation.
(Hardness)
2. Resistance to abrasion.
(Wear resistance)
3. Plasticity.
(Fracture resistance)
Note that some attributes will affect others. Harder metal will also be more wear resistant, and will roll less, but may just chip instead.
Toughness is the combination of hardness and fracture resistance.
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I like 20 degree angles on everything, easy to resharpen and holds a mean edge from Choppers to Skinners thats what is on most everything I own except my boning/filet knives they get 15 degrees so they slice through like butter, wasted meat is wasted money.