best degree angle for a knife bevel

[hazlitt777]

I sharpen my own knives. I can set the angle of my KME sharpener to 25 or 30% angles. What is a better angle for the cutting edge, 30% or 25% in your opinion.

thanks,
Joe

 

[ROBB]

It all depends on what you're cutting.

 

[Obsessed with Edges]

It all depends on what you're cutting.

This.^

Also depends on steel type & hardness, HOW you cut (push-cutting, slicing, chopping) and, above all, personal preference.

When in doubt, it's generally safe to start at 30° inclusive (15° per side) with most any blade/steel type. Depending on how you perceive the edge to be performing, then decide if it's too thick or too thin. If the edge is rolling or chipping too easily in use, that's a good indication it's too thin for your purposes. On the other hand, if it's seemingly not wearing much or rolling/chipping, but it's also not cutting as well as you think it should, then it should be safe to thin the edge angle a little bit more.


David

 

[Jason B.]

I hope those are inclusive angles because if that's per side angles you would have a rough time getting a sharp edge.

 

[Obsessed with Edges]

I hope those are inclusive angles because if that's per side angles you would have a rough time getting a sharp edge.

Good point.^

I hadn't considered if OP is referencing per-side angles. If so, either 25° or 30° (50°/60° inclusive) is likely way too thick, for most knives. Looks like the KME might be set up for per-side markings (17-30, according to the web site; that mirrors Lansky's clamp setup as well, which is 'per side' on that system).


David

 

[fluid_motion]

I don't do alot of hard use so i tend to put a 30 degree inclusive edge on most of my knives. the few that see harder use get a 36 degree inclusive edge

 

[Jason B.]

I don't do alot of hard use so i tend to put a 30 degree inclusive edge on most of my knives. the few that see harder use get a 36 degree inclusive edge

Thats a good angle to keep at.

 

[Twindog]

I've always reprofiled my edges to 30 degrees inclusive. But I'm starting to change my thinking on edge angles. A week ago, my malamute broke his leash, popping three reinforcing rivets. I tied the lease back in place, then realized that I hadn't rethreaded the retracting mechanism. So I cut off the leash end with my Sebenza to start the process over. It's a large Sebenza, with mostly the original convex edge (which is roughly equivalent to 15 dps). I've maintained that edge with a 40-degree inclusive micro-bevel.

Even though the edge was sharp enough to easily slice newspaper, it was extremely difficult to cut off the leash, which uses a heavy-duty strap that has seen a of years in the sun and rain. I may have hit a rivet, I don't know. But when I finally did get the leash cut off, the entire edge was rolled. There was no sharpness left at all. It was like a giant burr or wire edge, but much heavier and rolled more severely. The edge was literarily like a butter knife. I steeled it back in place with considerable effort, but the idea of losing an entire edge on one cut worries me. I know I'm going to have to regrind the whole edge, and there is not a lot of edge to regrind on these hollow-grind blades.

I know Sebenza's use softer steel than most knives with powder steels. Mine is rated at 58-59 Rc. The edge width is 0.017 inches, so it's an acute edge. That edge geometry cuts really well, but it's not robust.

My latest knife, a ZT 801S110V had a relatively thick blade profile, so I used a 40 dps edge when I reprofiled it. I'm thinking about going that that heavier edge on my other knives.

 

[Jason B.]

I've always reprofiled my edges to 30 degrees inclusive. But I'm starting to change my thinking on edge angles. A week ago, my malamute broke his leash, popping three reinforcing rivets. I tied the lease back in place, then realized that I hadn't rethreaded the retracting mechanism. So I cut off the leash end with my Sebenza to start the process over. It's a large Sebenza, with mostly the original convex edge (which is roughly equivalent to 15 dps). I've maintained that edge with a 40-degree inclusive micro-bevel.

Even though the edge was sharp enough to easily slice newspaper, it was extremely difficult to cut off the leash, which uses a heavy-duty strap that has seen a of years in the sun and rain. I may have hit a rivet, I don't know. But when I finally did get the leash cut off, the entire edge was rolled. There was no sharpness left at all. It was like a giant burr or wire edge, but much heavier and rolled more severely. The edge was literarily like a butter knife. I steeled it back in place with considerable effort, but the idea of losing an entire edge on one cut worries me. I know I'm going to have to regrind the whole edge, and there is not a lot of edge to regrind on these hollow-grind blades.

I know Sebenza's use softer steel than most knives with powder steels. Mine is rated at 58-59 Rc. The edge width is 0.017 inches, so it's an acute edge. That edge geometry cuts really well, but it's not robust.

My latest knife, a ZT 801S110V had a relatively thick blade profile, so I used a 40 dps edge when I reprofiled it. I'm thinking about going that that heavier edge on my other knives.

I would not recommend doing so, increasing you're edge angle making it a more obtuse geometry will only add to the binding effect on any material that is deeper than the cutting edge.

Because the S30V is softer a Coarse DMT finish followed by some stropping while keeping you're 30 inclusive angle with result in much better performance, I will give you a year of free sharpening if it does not.

 

[Twindog]

I would not recommend doing so, increasing you're edge angle making it a more obtuse geometry will only add to the binding effect on any material that is deeper than the cutting edge.

Because the S30V is softer a Coarse DMT finish followed by some stropping while keeping you're 30 inclusive angle with result in much better performance, I will give you a year of free sharpening if it does not.

Thanks, Jason. I'll give it a try. I use the Wicked Edge to sharpen, and I don't usually like the results until I get up to the 1600-grit ceramics. That's when the edge really begins to grab.

I tried sharpening the Sebenza after steeling the edge straight, and it didn't do well with the Sharpmaker at 40 degrees inclusive. I'm guessing that the edge metal was damaged quite a bit by severe rolling. Under a 10X loupe, I could see microchipping, as well.

My rethinking of the final edge angle is to put more emphasis on the edge width of the shoulders (behind the edge width), where most of the benefits from acute geometry seem to lie.

To be honest, I was shocked at how poorly the Sebenza edge held up at 30 degrees with a 40-degree microbevel inclusive.

 

[Obsessed with Edges]

Thanks, Jason. I'll give it a try. I use the Wicked Edge to sharpen, and I don't usually like the results until I get up to the 1600-grit ceramics. That's when the edge really begins to grab.

I tried sharpening the Sebenza after steeling the edge straight, and it didn't do well with the Sharpmaker at 40 degrees inclusive. I'm guessing that the edge metal was damaged quite a bit by severe rolling. Under a 10X loupe, I could see microchipping, as well.

My rethinking of the final edge angle is to put more emphasis on the edge width of the shoulders (behind the edge width), where most of the benefits from acute geometry seem to lie.

To be honest, I was shocked at how poorly the Sebenza edge held up at 30 degrees with a 40-degree microbevel inclusive.

I was never too happy with the factory edge on my S30V Sebenza. Also never really did much to improve it using the SM's ceramics. My opinion of the steel and edge didn't improve until I finally decided to thin it out and finish it on a Fine DMT, due very much to previously reading Jason's opinions on finishing it as such. I like the knife a LOT better now. The additional upside is discovering that this steel can so easily be thinned, repaired and finished on that single DMT Fine hone, with minimal or no stropping at all; makes it very easy to live with. I haven't yet tried finishing it with the Coarse DMT, but I'm sure that could work as well. :thumbup:


David

 

[Blue Sky]

..To be honest, I was shocked at how poorly the Sebenza edge held up at 30 degrees with a 40-degree microbevel inclusive.

I would be too except for the fact that there were rivets in play. Even at 30 degrees, from the damage you describe my guess is that you did indeed hit one. Would be easy to check, if you still have the cut off piece.

 

[Twindog]

I would be too except for the fact that there were rivets in play. Even at 30 degrees, from the damage you describe my guess is that you did indeed hit one. Would be easy to check, if you still have the cut off piece.

I was cutting off a knot that included the rivets. The actual cut, when I examined the strap, didn't hit any rivets that I could see, but I might have and probably did. I may have rolled it against the D ring, too. I was cutting along the D ring to avoid the rivets. But it was one cut that rendered the edge all but worthless. I've never experienced that before.

 

[Jason B.]

Steeling such an alloy probably didn't help either, it's not a recommended practice outside soft low alloy carbon and stainless steels. German knives, Old hickory carbon and the like.

 

[hazlitt777]

I don't know what you all mean saying 30 degrees inclusive. My KME sharpener sharpens the blade on both sides. So is that inclusive?

My knife is made of 52100 steel. Razor sharp. It is the bark river mountain skinner. See the picture below:

https://www.google.com/search?q=bar...ums%2Fshowtopic.php%3Ftid%2F787227%2F;576;454

I set my KME sharpener to 25%. I used the arkansas stone and it quickly restored a razor sharp edge to it. I skinned, quartered and then took all the meat off the carcass without every having to sharpen it. Amazing metal.

I'm hoping going with 25% was best, rather than 30%, for this kind of metal. What say you?

Thanks, Joe

 

[Obsessed with Edges]

I don't know what you all mean saying 30 degrees inclusive. My KME sharpener sharpens the blade on both sides. So is that inclusive?(...)

(Edited) 'Inclusive' is the sum of the two 'per side' angles. More than likely, your KME's settings are marked for the angle 'per side'; if so, the 'inclusive' angle will be 2X that marking (the sum of each side's angle).

An 'inclusive' angle of 30° would imply each side's angle will be 15°.

With guided sharpeners using clamps, the other variable is the position of the blade's edge relative to the clamp. Very wide blades that position the cutting edge further away from the clamp's front edge will sharpen at lower angles than a blade's edge positioned closer in to the clamp's front edge (all based on trig functions for the 'right triangle' formed by the clamp, blade and guide rod for the hone). All of this means that the actual angle on a particular blade will likely be something different than what the marked setting on the clamp implies, sometimes very different.


David

 

[Blue Sky]

I was cutting off a knot that included the rivets. The actual cut, when I examined the strap, didn't hit any rivets that I could see, but I might have and probably did. I may have rolled it against the D ring, too. I was cutting along the D ring to avoid the rivets. But it was one cut that rendered the edge all but worthless. I've never experienced that before.

I believe it. I had my GEC Bullnose out one day to cut a small bundle of something. Blade was decently sharp, 40 deg. included or thereabout. Turns out there was a thin steel wire (think like a twist tie) in the bundle and running the edge forcefully across that did the same roll job you described. It was thin, but it must have been hard.

Steel on steel does bad things to an edge.

 

[singularity35]

'Inclusive' is the sum of the angles of each side. More than likely, your KME's settings are marked for the angles on each side; if so, the 'inclusive' angle will be 2X that marking (the sum of each side's angle).

An 'inclusive' angle of 30° would imply each side's angle will be 15°.

With guided sharpeners using clamps, the other variable is the position of the blade's edge relative to the clamp. Very wide blades that position the cutting edge further away from the clamp's front edge will sharpen at lower angles than a blade's edge positioned closer in to the clamp's front edge (all based on trig functions for the 'right triangle' formed by the clamp, blade and guide rod for the hone). All of this means that the actual angle on a particular blade will likely be something different than what the marked setting on the clamp implies, sometimes very different.


David

A little more clarification. With clamped or guided angle sharpeners the angle indicated is usually degrees per side. That means that if the OP is setting his sharpener at 25º and it's degrees per side, his inclusive bevel with be 50º inclusive. Which is thicker than an axe bevel.

 

[rogerxd45]

A little more clarification. With clamped or guided angle sharpeners the angle indicated is usually degrees per side. That means that if the OP is setting his sharpener at 25º and it's degrees per side, his inclusive bevel with be 50º inclusive. Which is thicker than an axe bevel.

most factory knives use a 20-25 degrees per side, zero tolerance and kershaw said they usually use a 22 deg per side angle on most of their knives
benchmade uses a 30deg per side 60deg inclusive on most of their knives... yea thats right 30deg PER SIDE according to benchmade customer service, i made sure to double check that when they said it, i figured they meant inclusive but they confirmed its per side

for the average pocket knife i use 22.5 which is still shaving/slicing paper sharp. on my high end knives with better steel i use a 15 deg per side for a crazy sharp edge

there is nothing wrong with a 25deg per side edge. if you sharpen it correctly so its perfectly even and sharpened all the way to the apex it is plenty sharp and will hold that edge for a long time

i recommend asking the company what angle they use and sharpen to that angle unless you have the skill and tools to re-profile it to a new angle which can be VERY labor intensive even with the proper tools, trying to do it on a sharpener that isnt designed for re-profiling will make it very difficult to get an even edge all the way to the apex as you have to remove far more material then with a standard sharpening

 

[Jason B.]

most factory knives use a 20-25 degrees per side, zero tolerance and kershaw said they usually use a 22 deg per side angle on most of their knivesbenchmade uses a 30deg per side 60deg inclusive on most of their knives... yea thats right 30deg PER SIDE according to benchmade customer service, i made sure to double check that when they said it, i figured they meant inclusive but they confirmed its per sidefor the average pocket knife i use 22.5 which is still shaving/slicing paper sharp. on my high end knives with better steel i use a 15 deg per side for a crazy sharp edgethere is nothing wrong with a 25deg per side edge. if you sharpen it correctly so its perfectly even and sharpened all the way to the apex it is plenty sharp and will hold that edge for a long timei recommend asking the company what angle they use and sharpen to that angle unless you have the skill and tools to re-profile it to a new angle which can be VERY labor intensive even with the proper tools, trying to do it on a sharpener that isnt designed for re-profiling will make it very difficult to get an even edge all the way to the apex as you have to remove far more material then with a standard sharpening

Geometry is everything, 25 dps is fighting geometry and ANY knife you have such an angle on will suffer from very poor edge retention. Following the manufactures recommendation is almost always a bad idea.