Choosing an Edge Angle Based on Steel Type

[Bolster]

I've never had a very thoughtful approach to choosing an edge angle, often sharpening the edge of a quality pocket knife at 15 dps (sometimes with a back-bevel of 12-13) and an outdoor hard-use fixie at 20 (sometimes with a back bevel of 15). That's a fairly crude rule of thumb: folding or fixed.

The other day I was reading one of Larrin's archived articles, where he interviews Roman Landes, who has done extensive scientific testing on edge stability. Toward the end of Larrin's article, Landes presents a more thoughtful approach to choosing an edge angle than I've encountered previously.

He recommends steels with a low volume of small carbides (think 52100, AEB-L) get around 10 dps per side (ranging from 8-12 dps). But ingot steels with a large volume of large carbides (think traditional ATS-34, D2, 440C) get edges around 25 dps (range 20-30 dps). Finally, PM steels with a large volume of small carbides may ideally be sharpened around 16 dps (range 12-20 dps).

It's an interesting method of matching edge angle to steel type. If Landes is correct, I've sharpened some of my older large-carbide ingot blades at too steep/acute an angle! And some of my "cheaper" blades with low carbides are probably sharpened too obtuse.

Food for thought.



https://knifesteelnerds.com/2018/08/27/ ... stability/

[vivi]

I take my PM steels much thinner than that with no issues.

[Fireman]

The angle of the dangle is also based on use and abuse. My kitchen knives are LC200N aka Cronidur 30 and I go roughly 12DPS per my face balls hand sharpened and I factor that into my movements. I have 1095 and stainless steels at 15-17DPS. I factor in the totality of TBE, Angle and steel when I work. The only knife that is a beast of an angle (convex) is my F-Dick cleaver but that is still sharp enough to shave (but not cleanly)

[Bolster]

I take my PM steels much thinner than that with no issues.

Right, me too, but I think Landes was referring to maximum edge stability balanced against efficient cutting. (You can always get more edge stability by a more obtuse edge.) Whereas some of us "hot rod" our edges past maximum edge stability.

[Wartstein]

Not an expert, but I have experience with D2 and 440C, and 25 (or even up to 30!) per side sounds really unnecessarily thick to me if one still wants some actual cutting performance...

[Bill1170]

Not an expert, but I have experience with D2 and 440C, and 25 (or even up to 30!) per side sounds really unnecessarily thick to me if one still wants some actual cutting performance...

I agree, unless it’s merely a micro-bevel.

[marty_bill_]

I think hollow vs flat vs saber vs etc... All has a lot to do with it as well. The hollow grind on the xhp of my Swayback is awesome! I mean it's the sharpest Spydie I got and I'm wasn't thrilled about xhp. Xhp was not my go to steel. But blade shape and grind has totally made me a believer. I'm a Swayback guy now. Maybe forever?? Love the wharncliff design. Thinking I need a yojimbo or yojumbo even. Michael Janich thank you for making me a believer!!

[bearfacedkiller]

I have zero interest in an edge bevel over 30 degrees inclusive. If a blade cannot support that I won’t use it. I will run a small microbevel on that 30 degree edge but running the bevel itself at 40 degrees gives up too much.

[JonLeBlanc]

I don't have a way of measuring for sure, but I'd estimate I've got my user 52100 PM2 at about 12 dps. It whispers through things.

[Bolster]

Not an expert, but I have experience with D2 and 440C, and 25 (or even up to 30!) per side sounds really unnecessarily thick to me if one still wants some actual cutting performance...

Agreed, and that's why I brought it up for discussion. Now, I assume these obtuse angles for large-carbide steels are for the microbevel, but the article doesn't actually address microbevels.

But it does make me wonder if an ingot D2 blade, for instance, would benefit from a nice acute back-bevel (say 10-15 dps) and then finish it with an obtuse microbevel (say 20-25 dps).

[S-3 ranch]

Not an expert, but I have experience with D2 and 440C, and 25 (or even up to 30!) per side sounds really unnecessarily thick to me if one still wants some actual cutting performance...

Yep , this old cowboy, has lots of 440c , and carbon steel, and try to keep >30 combined

[Wandering_About]

I adjust edge angle much more based on intended use than on steel type.

[TkoK83Spy]

I tend to go anywhere from 12-17dps on just about any knife, regardless of steel. Haven't run into any issues yet. I feel most confident in the balance of 15-17dps range though.

[Chuck James]

I've been using M390, 20CV, XHP and Cruewear with a 17* to 18* bevel and 22* to 23* micro bevel. I don't carry my knives as pocket jewelry and find this angle combination to hold up very well with the abuse I put them through.

This applies to Spyderco knives only. I've not had as much success with other makers and the same steels.

[vivi]

Not an expert, but I have experience with D2 and 440C, and 25 (or even up to 30!) per side sounds really unnecessarily thick to me if one still wants some actual cutting performance...

Agreed, and that's why I brought it up for discussion. Now, I assume these obtuse angles for large-carbide steels are for the microbevel, but the article doesn't actually address microbevels.

But it does make me wonder if an ingot D2 blade, for instance, would benefit from a nice acute back-bevel (say 10-15 dps) and then finish it with an obtuse microbevel (say 20-25 dps).

I have a queen d2 stockman that I took to about 8dps on the wharncliffe and 10dps on the other blades. works great.

[The Meat man]

It makes sense as a general rule. But probably more important than steel type is the intended use. If you're going to be careful, and use your knife strictly as a cutting tool for softer materials then you should be fine with 10-15 dps, or even thinner. If you plan on using it more roughly, cutting harder materials which might put a lot of lateral force on the edge, then maybe make it more like 20+ dps.

In short, I'd sooner choose an edge angle based on intended use, than steel type.

[bearfacedkiller]

I have a custom puukko in ingot D2. It isn’t a true zero ground scandi since the edge itself is slightly convex. It is acute enough that the actual apex will hit the edge at around 25 degrees (12.5 dps). I have carved dried hardwoods with it and done some battoning with it and it has held up very well.

This has been eye opening for me. All the bench racers will tell you that this puukko wouldn’t have held up at all. I am one to study steel compositions and draw conclusions from them and in general that is trustworthy but there is still no substitute for real world testing. Every knife is different, every batch of steel is different, every heat treat is different and the actual geometry of every knife is different. You don’t know until you try.

I have a Becker BK9 in 1095CV with a 30 degree inclusive edge that has been beaten like it owed me money and the edge has never failed. It has chopped and battoned its way through a lot of dried hardwoods. I have beat it so hard with a baton the my hand hurt for a couple days. I try to wear gloves when I use it to protect my hands so I definitely don’t go easy on it.

Again, if a steel or a knife won’t support 30 degrees it has no use to me.

[vivi]

I have a custom puukko in ingot D2. It isn’t a true zero ground scandi since the edge itself is slightly convex. It is acute enough that the actual apex will hit the edge at around 25 degrees (12.5 dps). I have carved dried hardwoods with it and done some battoning with it and it has held up very well.

This has been eye opening for me. All the bench racers will tell you that this puukko wouldn’t have held up at all. I am one to study steel compositions and draw conclusions from them and in general that is trustworthy but there is still no substitute for real world testing. Every knife is different, every batch of steel is different, every heat treat is different and the actual geometry of every knife is different. You don’t know until you try.

I have a Becker BK9 in 1095CV with a 30 degree inclusive edge that has been beaten like it owed me money and the edge has never failed. It has chopped and battoned its way through a lot of dried hardwoods. I have beat it so hard with a baton the my hand hurt for a couple days. I try to wear gloves when I use it to protect my hands so I definitely don’t go easy on it.

Again, if a steel or a knife won’t support 30 degrees it has no use to me.

Same here. Every cutting tool I own with a 9" or less blade gets 15dps or less, with the exclusion of large axes. Hatchets, large camp knives, my Scrapyard Dogfather - all 15dps or less. So of course a 3" blade pocket knife will get an edge at least as thin as those harder use tools.

[kobold]

I don't have a way of measuring for sure, but I'd estimate I've got my user 52100 PM2 at about 12 dps. It whispers through things.

A quick measuring set up:

[Evil D]

I'd say every individual steel probably has an absolute perfect angle/grit finish that works best for it. How cool would it be to narrow that down into a database? I'm sure it also has to do with what you're cutting but there has to be a very good average for each steel. Categories do make sense though since similar steels like S30V vs S35VN might be so close to each other that they like the same angle/grit combo.