25 inclusive for EDC?

[kershawguy13]

What do you guys think of having a 25 inclusive back bevel with 40 inclusive micro bevel for EDC? Will it hold up to tasks such as cutting cardboard, opening packages, food prep, etc.? Thinking about sending off a few knives to have this done?

 

[Twindog]

That should work fine for those light tasks, especially if you are using a high-quality steel. If the edge doesn't hold up, you could deepen the microbevel.

 

[scamero]

I think it would chip/flatten/roll under harder use, I'm sure I'm in the minority with this thinking though. It also depends on how MUCH you microbevel at 20 ps. Also, doing this will likely give you wide bevels. Some like the looks, some don't.

 

[Obsessed with Edges]

What do you guys think of having a 25 inclusive back bevel with 40 inclusive micro bevel for EDC? Will it hold up to tasks such as cutting cardboard, opening packages, food prep, etc.? Thinking about sending off a few knives to have this done?

In all likelihood, YES, it'll hold up well enough. Most or all of my knives are at or below 25° inclusive, and I've been using them in the same types of tasks. I don't microbevel at all, BTW. Stropping with well-chosen compound is a good way to touch them up after use, so you don't have to regrind the edge too often. For tasks like cardboard cutting and plastic (clamshell) packages, you'll really appreciate the thinner geometry; it makes a big difference.


David

 

[kershawguy13]

In all likelihood, YES, it'll hold up well enough. Most or all of my knives are at or below 25° inclusive, and I've been using them in the same types of tasks. I don't microbevel at all, BTW. Stropping with well-chosen compound is a good way to touch them up after use, so you don't have to regrind the edge too often. For tasks like cardboard cutting and plastic (clamshell) packages, you'll really appreciate the thinner geometry; it makes a big difference.


David

I already had one Delica reprofiled to 25 and it does work great on cardboard.

 

[bgentry]

I've only got one blade that thin: It's my ZDP-189 Delica. It cuts like a demon. Well... a mini-demon. No microbevel. Just a standard bevel at ~11-13 dps == 22 - 26 deg-inclusive.

That blade is supposed to be really hard (something like 65 HRC) and it seems to hold up just fine, but I don't do much with it. Since I did the last lowering of the angles, I don't think I've even cut any cardboard. I should go destroy some boxes with it tomorrow. That'll give me an excuse to resharpen it and lower the angle a little bit more.

Murray Carter says several times in his videos something like this: "Lower the edge angle until it performs the way you want it to. If you somehow get low enough that your edges are easily damaged, you've done a very good job. Just raise the angle up a tad, and resharpen. Now your edge will be more durable. I've seen almost no-one lower the edge angle too much." Not a direct quote. Just close to what he said.

Cliff Stamp says his Delica is at some insane geometry like 7 degrees per side with a 10 degree micro bevel. This is from memory so don't quote me. I think I watched him cutting up old sand impacted carpet with it as a test and it held up "some". That was some AWFUL media to test a blade on.

My feeling these days (as the above implies) is that we can lower our edge angles MUCH more dramatically than a lot of people think and say and still have good edge holding.

Brian.

 

[Rapt_up]

I've only got one blade that thin: It's my ZDP-189 Delica. It cuts like a demon. Well... a mini-demon. No microbevel. Just a standard bevel at ~11-13 dps == 22 - 26 deg-inclusive.

That blade is supposed to be really hard (something like 65 HRC) and it seems to hold up just fine, but I don't do much with it. Since I did the last lowering of the angles, I don't think I've even cut any cardboard. I should go destroy some boxes with it tomorrow. That'll give me an excuse to resharpen it and lower the angle a little bit more.

Murray Carter says several times in his videos something like this: "Lower the edge angle until it performs the way you want it to. If you somehow get low enough that your edges are easily damaged, you've done a very good job. Just raise the angle up a tad, and resharpen. Now your edge will be more durable. I've seen almost no-one lower the edge angle too much." Not a direct quote. Just close to what he said.

Cliff Stamp says his Delica is at some insane geometry like 7 degrees per side with a 10 degree micro bevel. This is from memory so don't quote me. I think I watched him cutting up old sand impacted carpet with it as a test and it held up "some". That was some AWFUL media to test a blade on.

My feeling these days (as the above implies) is that we can lower our edge angles MUCH more dramatically than a lot of people think and say and still have good edge holding.

Brian.

I tend to agree, especially with higher performance steels, and better heat treat. I have a couple coming back that should be pretty darn amazing....

 

[Wowbagger]

25 inclusive and forget the micro bevel.
Sharpen them your self.
An EDC can need a touch up weekly or biweekly if you use it daily / often during the day.
If you have other people sharpening for you your knife(s) will spend all the time in the mail.

 

[Wowbagger]

ZDP-189 Delica. It cuts like a demon. Well... a mini-demon. No microbevel. Just a standard bevel at ~11-13 dps == 22 - 26 deg-inclusive.

That blade is supposed to be really hard (something like 65 HRC) and it seems to hold up just fine,

Yes but . . .

Watch out for cutting the larger wire ties. I have the same material in the Dragon fly. Love the knife but got a little chipping.

The really hard stuff takes some careful handling.
And that was the factory edge geometry; I had not sharpened it at all.

 

[Bob6794]

For those tasks it should hold up fine, I used to have all my knives set at 15dps and used some of them quite a bit and they held up fine. Though I have taken to putting a micro bevel on my work knife in my new job as someone i let use it managed to chip the blade so it now has a 25dps microbevel and it seems to retain a decent amount of the performance that way, in real world use I notice no difference. If your the sole user it's easy to get away with either, if you occasionally have to let others use your knife than I go with a micro bevel to make it a little more robust as people tend to abuse knives.

 

[Chris "Anagarika"]

Factory sharpening might result in weakened steel, due to using powered equipment. Usually a few sharpening session will get into good steel and should hold better.

Yes but . . .

Watch out for cutting the larger wire ties. I have the same material in the Dragon fly. Love the knife but got a little chipping.

The really hard stuff takes some careful handling.
And that was the factory edge geometry; I had not sharpened it at all.

 

[bucketstove]

Hi

I recently read about cliffs angle recommendations in Definition of edge thickness
My kitchen knives could withstand much lower/thinner angles
but my "staff" has too many years of practice with dull/thick knives,
the rate and depth of injury would increase too much
More comments after quote

-4 to 6 dps, light use knives, paper and cardboard, light ropes, knot free woods

-8 to 10 dps, hard woods, thicker plastic, heavy ropes

-12 to 14 dps, chopping blades

Keep in mind these are ranges, as there are a number of factors which influence them :

-<0.005", light use knives, paper and cardboard, light ropes, knot free woods

-<0.005"-0.015", moder push cuts on woods, thicker plastic, heavy ropes

-<0.015"-0.025", hard push cuts on very knotty woods, bones, etc.

->0.025" dps, chopping blades

Steel of course being one, weaker steels need more metal in the edge to keep them from deforming.

I've taken the dollar tree stainless knives I use to practice to 10dps, with 15dps and 20dps microbevels
They are something like 1/32 inch (0.03125") thick blades with flat sides
I've used them to whittle a really knotty/hard/ chairleg, the knotty part I couldn't dent with fingernail,
the edges didn't roll.
I could probably go much lower like cliff suggests,
just not in the kitchen, even 10dps is too efficient at slicing fingers :O

Just to put CliffStamps recommendations into perspective, this is how he tests it, 1000 slices into hardwood flooring, it takes me about 1-3 months of kitchen use to reach 1000 slices
Normark EKA 12C27 : optimal edge geometry for slicing hardwoods (norton economy fine edge) - CliffStamp

Published on Jan 3, 2015

This is an example of a set of experiments I typically use to determine the optimal edge configuration for a knife. In this case I want the hardest task to be cutting hard woods with high force and moderate twisting.

The first configuration is :

-knife full convex ground, edge is ~7 dps, 15 dps micro-bevel

This however leaves the edge too weak and it twists/deforms to a depth of about 0.005" at maximum. The second configuration is :

-apply a 10 dps secondary edge bevel, ~0.003" thick
-then a 15 dps micro-bevel

This is much better and after a couple of hundred passes there is only one small point of visible deformation. The third configuration is :

-apply a 12 dps secondary edge bevel, ~0.003" thick
-then a 15 dps micro-bevel

Now it does 1000 slices into the hardwoods with no visible damage. The edge and apex are both strong enough to resist deformation and thus the blunting is by slow wear. After 1000 slices the knife can no longer do a true push cut but does 45 push cuts and easily makes looping slices.

 

[kershawguy13]

25 inclusive and forget the micro bevel.
Sharpen them your self.
An EDC can need a touch up weekly or biweekly if you use it daily / often during the day.
If you have other people sharpening for you your knife(s) will spend all the time in the mail.

I don't have the tools to reprofile that low (25). I want a microbevel so I can keep it touched up on the Sharpmaker.

 

[REK Knives]

While I have not verified this myself I have heard and believe that professional felling axes are set to around 15 dps (on hard woods) and even lower down to 10-12 dps on soft woods. Of course, they have much more metal behind the edge (for chopping) but the edge itself holds up fine (normally ht and tempered in the knife range from what I have found). I don't think there will be any issue whatsoever going town to 12.5 dps or even 10 w/ a microbevel (although some disagree, it adds stability to the apex if you have pushed the apex beyond the point where it will roll/fracture/dent). I will be playing around w/ going down to the 10 dps range w/ elmax on my ZT soon, looking forward to it!

Ideally though, you would tune your knife to your needs specifically, with a regrind AND edge angle. You want it as thin as it can possibly go without being too weak for the hardest use you will put it through. In other words, an edge strictly for slicing cardboard would be designed w/ less metal behind the edge than one that you need to stick the blade under tie wraps/zip ties and twist the edge up into the plastic - this exerts a lot of lateral force which thin steel will not handle. This later knife would be left a little thicker.

That Delica i sharpened for you would drastically be improved in it's cutting performance with having the primary grind thinned out a bit =)

 

[scamero]

I knew I'd be in the minority, but I stand firm. Low angled edges have always chipped out on me in real world use and I no longer use them.

 

[awestib]

IMO given the endless variables (steel type, heat treatment, previous/factory sharpening etc.) you can not give a recommendation other than a ballpark as mentioned above. If you want to know the answer to your question, you have to reprofile your knife to try it out and adjust primary grind,secondary grind +- microbevel as needed to allow the blade to withstand what ever it needs to cut. That is also the beauty of owing and fine-tuning your knife, get used to it, know it.

As far as my experience goes, I would agree that a final apex angle of about 15 dps on an adequate thinned primary grind works for most tasks, not sure about twisting the blade under zip ties though. Given the better distribution of lateral forces against the apex, a convex/microconvex goes a long way to improve stability and most all hand sharpened edges have that mild convex shape anyway. Keep in mind that as soon as you strop your blade after proper sharpening you increase your apex angle once again.

 

[Obsessed with Edges]

The OP's described tasks (cutting cardboard, opening packages & food prep) are pretty standard & light work for most any typical knife. Cardboard cutting does most of it's damage through abrasive wear, which is independent of edge angle and only reflects the abrasion resistance of the specific steel type. The steel type & hardness would likely have a greater impact on chipping issues (previously mentioned ZDP-189 at 65 HRC being an example); most common steels at more typical hardness up through high-50s HRC wouldn't actually chip anyway under normal uses (if at all), and would only dent/roll under more abusive or harder work. I have a Case stockman in CV (mid-high 50s HRC) with a sheepsfoot blade thinned to ~ 20° inclusive (it's extremely thin), and even it holds up reasonably well in cutting cardboard, which is what I use it for most often, in addition to opening plastic clamshell packaging. It takes a little rolling of the edge at the very tip occasionally, but is easy fix on a compounded strop of hard-backed denim. What's gained in cutting efficiency with thinner geometry more than offsets any small increase in touching up a blade might need, the vast majority of the time.


David

 

[droptrd]

That will work great. Maybe a touch thinner than 25 too. Just don't over do the microbevel. Just a few passes ps with a very fine stone. You just want to cut off any burr from the back bevel - and not create a new burr.

 

[cbwx34]

What do you guys think of having a 25 inclusive back bevel with 40 inclusive micro bevel for EDC? Will it hold up to tasks such as cutting cardboard, opening packages, food prep, etc.? Thinking about sending off a few knives to have this done?

A boxcutter blade will pretty much do all that, and other than dulling, holds up pretty well. I'm sure your "better steel" knife will do just fine. (Plus, like a boxcutter, it will continue to cut to some degree, just because it's thinner.)

 

[REK Knives]

IMO given the endless variables (steel type, heat treatment, previous/factory sharpening etc.) you can not give a recommendation other than a ballpark as mentioned above. If you want to know the answer to your question, you have to reprofile your knife to try it out and adjust primary grind,secondary grind +- microbevel as needed to allow the blade to withstand what ever it needs to cut. That is also the beauty of owing and fine-tuning your knife, get used to it, know it.

As far as my experience goes, I would agree that a final apex angle of about 15 dps on an adequate thinned primary grind works for most tasks, not sure about twisting the blade under zip ties though. Given the better distribution of lateral forces against the apex, a convex/microconvex goes a long way to improve stability and most all hand sharpened edges have that mild convex shape anyway. Keep in mind that as soon as you strop your blade after proper sharpening you increase your apex angle once again.

I agree in that ideally you would fine tune your edge similar to this:

[video]https://youtu.be/Hy23qeCL1s8[/video]

I have reground my gayle bradley to .010" thick at 15 dps (hollow grind) and it could handle twisting under zip ties and even light chopping with no issues.