Edges: How thin are you comfortable with?

FortyTwoBlades

FortyTwoBlades

Baryonyx walkeri
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One thing I find with almost any knife that I own is that the factory edges are often nearly double the angle I would prefer to have them at. I thoroughly understand why they do it, but it raises the question of just how thin do members of the knife community feel comfortable with taking their edges for their particular set of general applications? It is extremely rare for me to have any tool with an edge greater than 15° per side, with most being closer to 10-12°, including on chopping tools used for woody targets. The tool and application dictates the angle, of course, but what range to most of your knives and tools fall in?
 
FortyTwoBlades said:
One thing I find with almost any knife that I own is that the factory edges are often nearly double the angle I would prefer to have them at. I thoroughly understand why they do it, but it raises the question of just how thin do members of the knife community feel comfortable with taking their edges for their particular set of general applications? It is extremely rare for me to have any tool with an edge greater than 15° per side, with most being closer to 10-12°, including on chopping tools used for woody targets. The tool and application dictates the angle, of course, but what range to most of your knives and tools fall in?
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16 per side for most except the fine grained carbon steels which I take down to about 12. Gotta support the carbides unless I want my knives to dull quickly.
 
For most of my EDC,lighter bushcraft that aren't scandi, knives I like about a 12 dpswith a V edge which stays sharp long is a good hard steel and slices like a mofo, my larger woods knives and hunting knives I do a convex 12-15 or so (I dunno, I do them on stones), and a my heavy duty choppers I like 15-17dps. Machetes get 15 dps and my gardening knives or shop knives get 20. I do prefer a thin thin edge. I think I have a -10 dps on my BK-11. I find the performance of a thin edge on my good knives negates the stress of frequent sharpening. If I'm out in the woods for a long time I will field sharpen a more robust convex edge because who wants to sharpen all the time.
 
I do not enjoy sharpening my knives often so I run a steeper angle on most of mine and strop often to keep sharp. 20 degrees on most except for my Moras which are all Scandi and pretty thin.
 
I almost always take my edges down to 15dps. Sometimes I'll place a secondary bevel at 18dps on my heavier duty knives.
 
I'm a lazy one, and since all my knives are S&W knives with inexpensive steel, I typically put them at 25 or 30 deg (Lansky sharpening kit, since I'm a noob) so that i only have to sharpen them once every 3 weeks or so.

Even with this angle, I can get them sharp enough to slice through paper without resistance, so I guess it's still ok. And anyway, the instructions on the sharpening kit recommends 25 - 30 deg for cutting through cardboard boxes, which is what I often subject my knives to.
 
I haven't done a lot of experimentation with specific angles but I put most everything from kitchen knives to EDC's to about 18-22.5 per side. For a chopper
I might resharpen it a bit thicker.
 
I used to screw around with edge angle a lot more. Now I pretty much profile everything to 30° inclusive and go from there. I don't notice that much of a performance increase from going lower than that, and I rarely see any edge damage at 15° per side, so no reason to go higher.
 
I haven't played around with angles a whole lot, but on any regular users I will typically reprofile the edge bevel freehand at something less than 15dps and then apply a microbevel at 15. There is typically a notable performance increase from the lower angle, but also because my slop from the freehand grinding will lightly convex the shoulders or transition from the edge bevel to the primary grind.

Also, I feel like the blade geometery in terms of thickness behind the edge is huge in terms of performance. Lately I have regrinding some knives to around 0.005-0.010" so that the edge bevel is very small. The blades suddenly cut much better and are much easier to sharpen and maintain with the small bevel. I'm increasingly annoyed every time I buy a new knife and it's got a fat bevel at 20dps and 0.020-0.025" behind the edge... (I don't mind that on an ESEE or something, but on a Spyderco?, come on. I just don't know what people are doing with their folders that would need that kind of geometry.)
 
There's no reason to go above 20dps on any knife, and I don't even like my knives that obtuse. I read a thread a while back where Sal Glesser said he keeps all his Spyderco's at 15dps, and never has issues no matter what the steel.

I'll use the factory edge for a short while on new knives, but it doesn't take long until I reprofile them to 30dps. I would probably go less than that, but the Sharpmaker won't accommodate it.
 
I even have my crappy steel(for the wife's and everybody's use) no name chinese kitchen knives at less than 15dps. Keeps cutting longer that way.
 
Edge angle only plays a small part, behind the edge thickness as measured at the shoulders of the bevel is the number I concern myself with.

I like knives with a thickness of .005-.015, any thicker and you end up with a knife that wedges more and is just troublesome to sharpen. Knives today with their "tacticool" flair and edges that average .030 behind the sharpened edge using the most advance steels only makes my head hurt. It makes me think these knife makers have never performed a cutting test or have even the slightest clue as to what good cutting geometry is. Using the best steel available, grinding it like a prybar then calling it a high performance tool really burns my a$$.
 
I am a serious newbie ... I convex my edges .. it works better for me , and since I sharpen with a hand held stone , not a professional sharpening system .. it convexes eventually anyway .
 
Jason B. said:
Edge angle only plays a small part, behind the edge thickness as measured at the shoulders of the bevel is the number I concern myself with.

I like knives with a thickness of .005-.015, any thicker and you end up with a knife that wedges more and is just troublesome to sharpen. Knives today with their "tacticool" flair and edges that average .030 behind the sharpened edge using the most advance steels only makes my head hurt. It makes me think these knife makers have never performed a cutting test or have even the slightest clue as to what good cutting geometry is. Using the best steel available, grinding it like a prybar then calling it a high performance tool really burns my a$$.
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How do you get the thickness behind the edge to be that thin on production knives like PM2, Delica, etc.? Does it require a full regrind of the blade?
 
Jason B. said:
Edge angle only plays a small part, behind the edge thickness as measured at the shoulders of the bevel is the number I concern myself with.

I like knives with a thickness of .005-.015, any thicker and you end up with a knife that wedges more and is just troublesome to sharpen. Knives today with their "tacticool" flair and edges that average .030 behind the sharpened edge using the most advance steels only makes my head hurt. It makes me think these knife makers have never performed a cutting test or have even the slightest clue as to what good cutting geometry is. Using the best steel available, grinding it like a prybar then calling it a high performance tool really burns my a$$.
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Well...I wouldn't say that edge angle plays a small part at all, though I agree with your sentiment. Technically the closer to the edge you get the greater the magnitude of influence specific geometry has on cutting performance. So yes, that's why a knife with a full flat grind will cut circles around a scandi grind of equal edge angle, stock thickness, and profile. But edge angle has a profound effect on cutting performance, even though it's not the exclusive factor at work. :)

But yeah, I hear ya' with thick geometries on so-called "high performance" tools. I think their definition of performance is very different from mine. :D It's one of the reasons why the first thing I pay attention to with a knife is the geometry--not the steel. It doesn't matter how nice the raw materials are if the form factor is lacking.

Edit to add: Using thickness at the edge shoulder can also be a little of a misleading benchmark depending on the overall geometry of the knife since changes in both edge angle and primary grind angle can cause the shoulder's distance from the edge itself to change. Measuring the thickness there can still be useful, but the dynamic has to be kept in mind and not used as the only metric. Measuring at a fixed distance behind the apex is usually a better way to figure things if you desire to go to the lengths of taking the readings. I usually just eyeball it/go by touch, but periodically will bust out the instruments to see where things are at so I have an idea of what I'm running the bevels at.
 
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ejames13 said:
How do you get the thickness behind the edge to be that thin on production knives like PM2, Delica, etc.? Does it require a full regrind of the blade?
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It depends. On a saber grind you can just work the primary bevel to thin things out and it'll just move the shoulder closer to the edge and the plunge line closer to the spine. In the case of altering the primary on a full flat grind you have to increase the angle of the grind (as funny as that sounds) or add an intermediary bevel (quicker, but less of a performance boost) in order to reduce the thickness behind the edge while preserving the full spine thickness.
 
I guess I could have stated that part a little better, edge angle does play a big part but in the current market I see blade geometry as the bigger issue, because in the long run it's a more important factor in cutting. My edge angle is about 18 DPS on folders and about 14-15 DPS on Kitchen knives. It has been a while sense I have had a Laser protractor but my actual apex angles were a few degrees high than what I was expecting from my spin heights and perceived edge angle. Edges I thought were sharpened to 10 DPS were a lot closer to 15, so unless everyone is using a laser protractor from CATRA all these numbers are inflated guesses, IMO :)
 
ejames13 said:
How do you get the thickness behind the edge to be that thin on production knives like PM2, Delica, etc.? Does it require a full regrind of the blade?
Click to expand...

A lot of Spyderco Knives will meet the requirements and if not the blade geometry is usually good enough to give it a good sharpening and be happy. My Spyderco K2 which is my current EDC has a 0.016 average thickness while my Spyderco Endura4 is 0.024 average. The Endure has been used and sharpened a lot so it's a little thicker but has a good blade geometry that still allows effortless cutting. Put that 0.024 behind the edge thickness on a Saber ground Endura and suddenly you have a splitting wedge.

Yes, I do regrind some knives that have excessively thick geometries.
 
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