The positive side of factory/thick edge angles with premium steels

Kaizen1

Kaizen1

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Keep in mind that this is not to knock those who like thinning out their edges, I personally like doing this myself.

I've read numerous times about the benefits of utilizing thinner edges for "premium" (S30V, S90V, ZDP, etc) steels because of their properties, primarily because of their ability to hold edges for ridiculously longer times than older "mediocre" steels (AUS4/6/8/10, 154cm, ATS34, etc).

While this is a great benefit of these newer steels, the general message that has been given by people who prefer this approach seems to be that it would simply defeat the purpose of keeping a factory edge or a thicker edge with them. One thing that I haven't read is that it would seem to me that there are some positive sides to keeping that thicker edge on. The main thing that sticks out for me is that edge retention would last significantly longer if we keep them thicker. To thin out an edge with a premium steel would still require one to touch up regularly to prevent one from having difficulty trying to get the edge back to a reasonable level of sharpness.

In other words, if we keep the edge too thin, then we'll have only low to medium amounts of increased edge retention and we'll have to constantly keep touching up the edge, which in itself if taken too far can defeat the purpose that brought a lot of people to that particular steel in the first place- edge retention. Keeping the edges thicker would require touch ups less frequently and allow lower maintenance.

Again, not knocking the thinner edge approach, just pointing out a benefit that I haven't read too much about when getting a super steel.
 
Kaizen1 said:
Keep in mind that this is not to knock those who like thinning out their edges, I personally like doing this myself.

I've read numerous times about the benefits of utilizing thinner edges for "premium" (S30V, S90V, ZDP, etc) steels because of their properties, primarily because of their ability to hold edges for ridiculously longer times than older "mediocre" steels (AUS4/6/8/10, 154cm, ATS34, etc).

While this is a great benefit of these newer steels, the general message that has been given by people who prefer this approach seems to be that it would simply defeat the purpose of keeping a factory edge or a thicker edge with them. One thing that I haven't read is that it would seem to me that there are some positive sides to keeping that thicker edge on. The main thing that sticks out for me is that edge retention would last significantly longer if we keep them thicker. To thin out an edge with a premium steel would still require one to touch up regularly to prevent one from having difficulty trying to get the edge back to a reasonable level of sharpness.

In other words, if we keep the edge too thin, then we'll have only low to medium amounts of increased edge retention and we'll have to constantly keep touching up the edge, which in itself if taken too far can defeat the purpose that brought a lot of people to that particular steel in the first place- edge retention. Keeping the edges thicker would require touch ups less frequently and allow lower maintenance.

Again, not knocking the thinner edge approach, just pointing out a benefit that I haven't read too much about when getting a super steel.
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I think "ridiculously" longer compared to 154CM and ATS-34 is a huge stretch. I have all and for the most part its a wash. Depends on heat treat, geometry etc. S30V is good but far superior...no.

As a matter of fact, my Marlowe custom holds an edge better than my new ZT301 (S30V) and its 154CM. I will agree that they AUS line is definitely mediocre for fine cutting but its tougher than S30V.
 
It's late and I've had a few, but the advantages as I understand them are:

Better steels will have better edgeholding than lesser steels if edge and blade geometries are the same.

Better steels can support thinner edges (which, of course, will cut better) than lesser steels.

So, if you want edge retention, like you say, don't thin out your edge.

If you want a thinner edge that will cut more effectively, thin it out and maintain it regularly.

I think a lot of the improvements in stainless steels are lost on clods like me- I'm not refined enough to write an essay on the differences in edgeholding and sustainable edge geometry between 154CM and S30V, say, 'cause I can't tell too much of a difference between the two. They're both better than I deserve. :D

JR
 
How exactly thicker edge would benefit edge holding? Obtuse angle may benefit the edge holding over the acute angle, but thickness?

Even if you keep the factory edge (i.e. the same angle) and just grind out the "shoulders" you are making it thinner.
 
If all we are doing is shaving our arms it is moot..... Use ... daily need... Cutting cardboard or envelopes is a world away from brush... catus.. rubber... roots... Good steel is good steel.
 
If I may voice my dissent,

Thicker edges have more contact with the materials they cut. That makes them require more force and forces them to experience more wear. It's not that the edge will last longer (it will be worn down quicker), it's that the loss of sharpness won't be as readily apparent. If your super-thinned ZDP (or D2 or 13C26 or whatever's hot right now) blade goes from needing one inch-pound of force to make a cut to needing three inch-pounds of force, you'll notice right away. If your sharpened-shovel edge of the same steel goes from needing 18 inch-pounds of force to make a cut to 20 inch-pounds of force, it'll feel the same (if you're sensitive enough to tell the difference, you wouldn't use an edge that thick anyways).

Thicker edges are good because they resist damage better than thin edges - just not at the very edge. :)
 
I disagree also. A thin edge will cut with less effort than a thick edge, with sharpness being equal. And when the thin knife dulls to the point where it will cut just like the thicker edge does initially, I think the thin edge will still hold that edge longer than the thick edge.

The only time a thicker edge has better edge retention than a thin edge is when the cutting task damages the thin edge and will not damage the thick edge.
 
huugh said:

How exactly thicker edge would benefit edge holding? Obtuse angle may benefit the edge holding over the acute angle, but thickness?

Even if you keep the factory edge (i.e. the same angle) and just grind out the "shoulders" you are making it thinner.
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I think that's the right approach to benefit from the properties of premium steels - essentially compound bevels.

For slicing, most of my blades have main bevels of 10 degrees. The final edge bevels are usually 15 degrees - but final bevels of 20 degrees make little apparent difference in apparent/felt slicing 'sharpness'. I attribute this to the thinner edge provided by the 10 degree main bevels.
 
Depends on what you cut. If it's a beater and you chop nails sticking out of a board with it or it hits staples regularly while breaking down shipping cartons, then yes thicker edges won't be damaged as quickly. On the basis of "normal" use like clean wood(no dirt or rocks) food, paper, etc the thickness of the edge hurts more than it helps. Both will blunt via wear at the same rate, but the thinner ground edge will keep cutting longer as the steel behind the edge is thinner.

edit: I'm using thickness to describe edge angles, not the actual thickness of steel behind the edge. I don't think that has any real effect on edge wear with the exception of gross abuse (chopping steel bars, etc). There's a point though at which the steel can be too thin and get easily damaged but I've only had that happen on a zero-ground CPM3v blade.
 
huugh said:
How exactly thicker edge would benefit edge holding? Obtuse angle may benefit the edge holding over the acute angle, but thickness?

Even if you keep the factory edge (i.e. the same angle) and just grind out the "shoulders" you are making it thinner.
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I was referring to the edge and not the shoulders. Sorry for the lack of clarity.
 
Broos said:
I disagree also. A thin edge will cut with less effort than a thick edge, with sharpness being equal. And when the thin knife dulls to the point where it will cut just like the thicker edge does initially, I think the thin edge will still hold that edge longer than the thick edge.

The only time a thicker edge has better edge retention than a thin edge is when the cutting task damages the thin edge and will not damage the thick edge.
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thombrogan said:
If I may voice my dissent,

Thicker edges have more contact with the materials they cut. That makes them require more force and forces them to experience more wear. It's not that the edge will last longer (it will be worn down quicker), it's that the loss of sharpness won't be as readily apparent. If your super-thinned ZDP (or D2 or 13C26 or whatever's hot right now) blade goes from needing one inch-pound of force to make a cut to needing three inch-pounds of force, you'll notice right away. If your sharpened-shovel edge of the same steel goes from needing 18 inch-pounds of force to make a cut to 20 inch-pounds of force, it'll feel the same (if you're sensitive enough to tell the difference, you wouldn't use an edge that thick anyways).

Thicker edges are good because they resist damage better than thin edges - just not at the very edge.
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This is interesting and does make sense. Has anyone done any side by side comparisons?
 
All I can say is, if you're so worried about cutting efficiency the amount of effort it takes to make a cut -- what's the matter -- ya got weak wrists?! ;)
 
Kaizen1 said:
This is interesting and does make sense. Has anyone done any side by side comparisons?
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Not in a competent manner, but....

I generally grind my pocketknives as thin as my skills, imagination, and kit will allow and then polish up the edge in a similar manner. When the edge fails (rolls, chips, or both), I regrind at a slightly thicker angle and apply the same level of polish (which is actually a higher level at the edge because the furroughs ground a higher angle can't go as deep) and if the edge holds, that's cool. If it doesn't, I eventually end up with a micro-bevel that's 25-30 degrees per side instead of the 24 degrees total (like with my S30V Native).

KeithAM said:
All I can say is, if you're so worried about cutting efficiency the amount of effort it takes to make a cut -- what's the matter -- ya got weak wrists?!
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I didn't before I chose thin-edged knives, but did experience a period of disuse atrophy in the muscles that move my wrists. I just hit the weights harder instead of thickening my edges and now my thin-edged knives skill cut the same, but now my khukuris feel way lighter. Win-win.

Buy the way, if you're using a knife, you're using a tool that reduces the force that's needed to separate what you're cutting. Why use a knife at all? And why drive when you can sprint? And why chew your food? Esophagus too delicate? Stomach too wimpy? Why breathe air? Lungs too pathetic to inhale the oxygen out of rust? That's the whole point of having a carbon knife - so I can take a breather when I'm done using it.... :p
 
Thin edge vs thicker edge can be argued all day long and into next year. just find the edge tjhat you like and don't worry about it.
 
I have been thinking lately, as my knives are users and i like them sharp, about putting a larger angle on the blade nearer the handle for heavier work and a finer angle at the tip for skinning or field dressing game. About half and half would seem right. Has anyone tried this?
 
Pops,
I have a few that I will polish the tip for push cuts and closer to the ricasso leave more toothy for slicing, but not really more obtuse.

Shane
 
thombrogan said:
I didn't before I chose thin-edged knives, but did experience a period of disuse atrophy in the muscles that move my wrists. I just hit the weights harder instead of thickening my edges and now my thin-edged knives skill cut the same, but now my khukuris feel way lighter. Win-win.

Buy the way, if you're using a knife, you're using a tool that reduces the force that's needed to separate what you're cutting. Why use a knife at all? And why drive when you can sprint? And why chew your food? Esophagus too delicate? Stomach too wimpy? Why breathe air? Lungs too pathetic to inhale the oxygen out of rust? That's the whole point of having a carbon knife - so I can take a breather when I'm done using it.... :p
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Yours, Sir, is a truly noble crusade. ;)
 
I try. Was feeling light-headed this morning, so I grabbed a 20 pound block of ice to breathe and left the remaining solid hydrogen in a bag. It must've melted and floated off somewhere because I can't find it now.
 
I'm certainly convinced after years of trying to cut tomatos with a rolling pin. But then I suppose I could have tried thinning it down before I took the radical step of switching to a knife. ;)

But your point is clearly valid. The next obvious step is no-effort gas pedals in cars. Why bother driving a car when you have to wear your ankle out overcoming that darn spring to accelerate!

We should make "Save your wrists, thin your edges" blacelets and bumper stickers!
 
Using a knife for food? After you choke out food, you should twist its head off, reach in for your fill, and drop the remains of the cadaver at the feet of your grateful pack as your gift. Then go inhale the oxygen out of glass and take a nap.

OR.... Keep going "Ooh do you have weak-wrists? Ooh-hoo! Degenerative arthritis? Tendonitis? Schweebeebeebeebeebeebee...."

Enjoy your bracelet making.
 
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