Sharpening Myths

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Vivi

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I just purchased internet service and with it comes some webspace for me to use. One thing I'm quite interested in doing is making a knife page for posting reviews, photos and sharpening tutorials. One section I wanted to include was a sharpening myths section. Since coming here and learning how to sharpen knives I've come across a few. What are some you know of?


1. A duller edge is more durable in hard-use knives / axes than a very fine, sharp edge. I have not ever noticed this effect in use. The sharper, finer the edge, the longer it lasts in any type of use according to my own experience.

2. Factory edge angles are "good enough." For someone who is educated enough about knives to be considering reducing the angle of the secondary bevel, I find such a notion false. Most factory knives, whether it's a swiss army knife or 100$ Spyderco, have thick edges to compensate for the type of use the "average joe" will put them through. Someone who is careful with his knives and understands the limitations of the steels should be able to utilize 20 degree inclusive[/i] edges without any problems.

3. A highly polished, scary sharp push cutting edge is the best type of edge for a knife. In many cutting applications a slice is used rather than a push cut. If a user or even a specific knife uses slices more than push cuts a lower grit edge will have much better slicing aggression and fit the tasks at hand more appropriately.

4. Freehand sharpening is difficult. With practice, is becomes rather easy with most blade shapes. :)
 
Cool idea Vivi:). I'm not sure how much help these are, but I've noticed people doing or saying the following:

Running your finger across a blade perpendicular to the edge is a way to determine if the edge is sharp. I believe this is generally an attempt to feel for a toothiness in the edge, which doesn't necessarily tell you that the edge is ideal.

If it can slice paper, it's sharp. When I go to friend's houses, sometimes I check out their kitchen knives and the majority of the knives can't even slice paper. So when someone is used to using dull edges such as those all the time, they tend to get blown away with how "sharp" a knife is when it can slice paper, even if it catches:rolleyes:. Though it generally is sharp enough to cut, I certainly wouldn't call it sharp.
 
I agree with all except #3, only because I think that myth is a myth. All the guys I deer hunt with know the value of a slicing fine grit edge. What they and many of my non-knife friends aren't familiar with is some of the things a razor sharp edge on a knife CAN do (they've never had one), or how long some good knives can maintain that edge!
 
its a cool idea but the issue i see is that a lot of these things is a lot of personal preference and the situation the knife/ax/other tool is put through, and some of it is choosing durability or fine sharpness but not easily getting both

but another one is the micro bevel, my sog came with it (at least i think so, it looked like it... like its sooooo easy to see) and it seemed to stay sharp well.

-matt
 
I agree with Broos. In my younger days I remember some of my hunting buddies saying, "this is as sharp as it's going to get", in frustration. Refering to the sharpening tech of the time. Refering to the higher Rc's being intro'd into the general market, ie 440c, this difficulty, to sharpen to a razor's edge. Would cause a user to rely on the coarser grain structure to accomplice the slicing.
 
Nice list.

Point #3 is certainly controversial, but to me, it means the edge either wasn't thin enough to do the type of cutting and/or the wrong material for whatever reason (heat treat, steel type, day of the week) to take that thin-enough edge, but the user had enough common sense (and therefore can't be considered a knifeknut) to make the best with what he or she had available.

I'd like to add that it's a total myth that convex edges are hard to make or maintain - it's harder not to make them!
 
Hi, Vivi
I think 1.) is worded a bit "clumsy" (I don't mean this as critique, more as a suggestion that you might want to think how to phrase this unambiguously, hope you know how I mean it :o). I think "dull" and "fine edge" are not opposites. I associate (might just be me) with fine edge either a polished edge (as in the opposite of a coarse edge) or one that is finely ground out and there for refers more to the thickness behind the edge than to sharpness. With that understanding I would disagree with the statement as I think that a chopper should have more meat behind the edge than a fine slicer.

I would also my two favorite myths:
A) A softer/less abrasion resistant steel is easier to sharpen.
It is easier to grind, but it might be a b*+# to get sharp
B) A rolling edge is preferable (easier to fix) than a chipping edge.
Not exactly a purely sharpening myth but it is related. Either way it is a matter of how bad the damage is: A dent in the edge due to a badly rolled edge is often more work to get out than a few micro chips. Pushing it out with a steel is often possible with a rolled edge but still useless, as it leave badly weakened material which is either prone to roll on first contact again or might even tear out (had that happen on a soft kitchen knife) and leave a much larger damage than if you had fixed it right in the first place.
 
One myth I'll mention: that convex edges and/or grinds enjoy some significant performance advantage unrelated to the underlying acuteness and cross-section of the edge or blade.
 
thombrogan said:
Ooh! Don't mention that one! Now the Convexarati will come and getcha! :eek:
Click to expand...
I steeled (braced? maybe honed?) myself for that. But I knew I could count on you to jump in with a rousing defense of the case, Thom. :D What's interesting, I don't consider this in any way a criticism of convex edges -- happen to like them on certain blades, as you point out they're often easier to apply, so IMO they definitely have their place and real, practical value. But alas, there's no pixie dust majick to be had there.
 
It seems obvious that the lack of consensus makes a collection of myths troublesome from the start. Anyone willing to embark on such an endeavor must be willing to endure the Cliff Stamp treatment from every direction.
 
You're only making it worse! Now hush up and start stropping on a phonebook over a mousepad suspended on the slack area of a belt grinder before they catch you! :eek:

I'd like the meet the person who makes flat edges when free-handing - the one whose definition of flat matches the dictionary. Flat enough? So long as it's sharp enough for what's being cut, it's sharp enough and flat enough or convex enough, but so long as every joint in our bodies move in arcs, so long as our hearts forcefully circulate blood through out bodies, so long as the soft tissues in our bodies have compressive qualities, and so long as our precision is determined by our nervous systems, we're going to end up with convexed edges when we do a good sharpening job.

The person who can make a completely flat edge when freehand sharpening is a flash-frozen zombie with servo-controlled prosthetic arms.
 
shecky said:
It seems obvious that the lack of consensus makes a collection of myths troublesome from the start. Anyone willing to embark on such an endeavor must be willing to endure the Cliff Stamp treatment from every direction.
Click to expand...

Which treatment? Cliff's questions and statements or his lack of popularity with certain people?

Whichever way, the problem with shattering myths is that it's a fine and easily crossed line between shattering legends because you want to see and spread the facts and shattering them because you like breaking stuff.
 
I'm with you guys on the convex edge points. Hard (unless you have those servo wrists & arms) not to do one without a jig, and thickness rules the cutting equation versus whether it is convex or not.

I may add another one that may not get much love, but I think needing steel with high toughness for a knife is somewhat of a myth. Steel toughness is often overrated as a knife quality.

How tough does a knife have to be for various uses? I have never seen this quantified with a number, yet have often heard some of the less tough steels discounted because they are not "tough enough".

When many big choppers made out of D2 or 440C have given good service to many users over many years (I have one in 440C that has chopped a lot and not broken yet), I think toughness should be a consideration, but is often overrated.
 
I dont think anyone has a problem with "shattering myths"..as long as it done scientifically ( what I mean is, something done in a repeatable manner by machine, not by hand, to remove the variables) and in a non condescending manner. Both of which a certain person had problems with.
 
thombrogan said:
Which treatment? Cliff's questions and statements or his lack of popularity with certain people?
Click to expand...

Both. Cliff seemed to rub everyone the wrong way.

thombrogan said:
Whichever way, the problem with shattering myths is that it's a fine and easily crossed line between shattering legends because you want to see and spread the facts and shattering them because you like breaking stuff.
Click to expand...

This is one problem. Lots of folks are simply offended by destructive tests. Some folks are offended because they have a dog in the race and are scared of the results.

I dont think anyone has a problem with "shattering myths"..as long as it done scientifically ( what I mean is, something done in a repeatable manner by machine, not by hand, to remove the variables) and in a non condescending manner. Both of which a certain person had problems with.
Click to expand...

Another problem. Stamp was about the ONLY person offering anything resembling hard data to back up his claims. When folks didn't like the claims, I can't recall anybody ever offering different data in a serious way, only personal attacks. Of course, Cliff's manner didn't help things any.

Shattering myths is bound to cause hurt feelings around here. Half the folks will subsequently never take the results seriously. This includes folks who earn their livelihoods making knives. In the end, almost nobody is interested in serious answers. Mostly folks want to be reassured of their own opinions.
 
thombrogan said:
.

I'd like to add that it's a total myth that convex edges are hard to make or maintain - it's harder not to make them!
Click to expand...

Thats a come to Jesus statement. I have found such freedom by not fighting the natural formation of the convex edge. Instead by embraceing it I soon discovered there was no spoon.
 
1. It is not a myth, and it is a myth – depending on to what, and how, you are using your knife. I lived outdoors for about 6 month at the time. I hold my knifes about 95% sharp and that works perfect for me (and all other people I know who live like this). The edge I make on them holds for a long time and I can use my knifes to hard work when I need to without sharpen them all the time. I can also trust the edge with my life, and sometimes I need to. People who use a 100% sharp edge in this type of life will soon learn that the edge will not hold. In today’s modern world people use their knifes differently. Sometimes per year they cut some branches, make some barbeque sticks and so on, their knifes can be 100% sharp and they will hold the edge because of the fact that the knife is really not so much in use – and – they have no demands to trust their knifes with their lifes….

2. Factory edges is mostly machine made in mass production and it is a standard machine made edge. It seams to be sharp but that is often micro teeth who make the edge “sharp”. It is very often, sorry to say, needed to sharpen the edge properly on new knifes. (All knifes is not like this – but most knifes is like this). If it is good knife producer, the edge angle is correct calculated for the knife – so just keep the edge angle and take away the micro teeth.

3. It depends on the use of the knife, se point 1.

4. Freehand sharpening is not difficult at all – but you must really know and understand what you are doing – and you really must know what the result will be. If you absolutely want to have a perfect straight edge – you cant sharpen by free hand because what you will get is a slightly convex edge – what ever you do. I have met hundreds of people who climes that they can make a flat edge by free hand – but I have never seen it be done. When I have measure the edge – it is slightly convex. This is because the human hand cannot hold better angle then 3 degrees variation when sharpening freehand = the edge will be convex. At least Scandinavian hands work like this… If you study old knifes, you will se that all of them have convex edges.

Then the big question.
What is sharp for me and what is sharp for you. Sometimes when I say that my knifes is 95% sharp people ask me how I can use knifes so dull. Then they give me their knifes and they look very proud and say : look at this knife, it is razor sharp! When I check the edge - it is about 75% sharp….

My knifes holds about 5 years. After that I have grinded away about 1/3 of the blad and it is time for me to make a new knife. All people I know who live like I did have the same experience. They are knife users – and the lifetime for a knife is then about 5 years. This is not because we rape our knifes, we do not, we take very good care about our knifes, but, we use them a lot, 100 times a day 365 days a year, year by year. That also means that we must sharpen them a lot. When you sharpen a knife, you will grind away material from the blade every time you do it = the blade is slowly grinded away.

Sometimes people show me knifes and say that this is a high quality knife and they have use it for 20 years and it is as new…. Then I know that this man have really never used his knife at all, he have just carried it around in his belt for 20 years.

So, in your points 1-4, you are correct – and incorrect - at the same time.

If you think about how knifes normally is used in our modern society – you are correct because today’s people do not use their knifes so often – and when they use their knifes it is to do things who fits in to our modern lifestyle.

Then, edge angles are different from country to country. In Scandinavia the normal edge angle is about 20 degrees (10+10) on knifes. In other cultures the edge angle is often higher, seldom lower. = I talk about the edge angles I use my self = 20 degree. For a belt knife with secondary bevel this is about 24-26 degree flat cutting edge, or, about 26-28 slightly convex edge. (I use slightly convex edges my self).

Thomas
 
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