Having trouble with forming a burr.

Arrrgghhh! All this burr dogma!

IMO (note that qualifier) raising a burr is a convenient, simple, and mostly harmless means of determining that you've sharpened to the very apex of the edge.

I believe you can, sometimes, tell a little something about the steel/blade itself by the burr or lack thereof: for example, large, heavy, stubborn burrs suggest a soft or gummy blade steel that probably won't have good edge retention; however if a blade isn't forming a burr you may have badly damaged steel from stress or corrosion.

Raising a burr is not absolutely necessary to sharpening, again it's just a handy means for some people to gauge their progress. It doesn't waste a huge amount of steel, IMO, unless you go really overboard ... over the life of your knives, chipping, rolling, impaction and other damage and wear from use will be the greater enemies of a blade's longevity.

The burr itself can introduce a few problems of its own -- that being, it has to be removed completely and cleanly before a high quality, lasting edge can be obtained. So if you can sharpen all the way to the apex without needlessly forming burr, you may make less work for yourself.
 
When changing edge geomtries it can be helpful to raise a burr. This is a physical indicator that the edge has been reached. However, I almost never use that technique when resharpening a blade at a known and undamaged angle. Many of the harder steels I own do not easily form a burr at the higher grits used and would require increased metal removal (and likely pressure) to form a burr. I think saying that you must raise is a burr is a bit silly, but in raising a burr you have a simple indicator that you have done your job.

Dog of War is dead on.
 
sputnick said:
. I think saying that you must raise is a burr is a bit silly, .
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While Im sure that there are some steels that cant be sharpened in the normal manner...still,,,I would ask for the name of a knife maker of note, or of a book, or website that has any information that might call into question the need to raise and then remove a bur as I have posted about?

As far as I have seen...with both the most well known bladesmiths on this forum as well as well know knife sharpeners like John Juranitch, the case supporting the need to both raise a bur and then clean it off, is very strong.

In fact I have yet to find even one author who is known as a leader in the knife sharpening business that does not list the very important need to raise a bur before going on to the next steps in sharpening a knife...

I would also suggest that anyone who thinks they dont need to get a bur, or who dont think they get a bur when they sharpen their own knives, really needs to have a look at what the latest science has learned
http://mse.iastate.edu/fileadmin/www.mse.iastate.edu/static/files/verhoeven/KnifeShExps.pdf
The truth is that all forms of sharpening will raise a bur.
The trick of sharpening is to understand how the bur can be used to help guide things along.
 
"Formation of a uniform bur along the sharpened edge indicates that the sharpened face has been extended uniformly out to the edge.The bur formation is easily detected by the well trained eye or the use of a fingernail and serves as a good guide for determining when to flip the blade over and grind the opposite face." [Verhoeven, p4, KniShExp]

As i've noted, the formation of a bur is a good INDICATOR. Perhaps the real debate here is one of scale. When a bur gets to the point that i can detect it either by eye or by touch, it has already been there for a while i simply couldnt tell because it was too small. The properties of steel are well known. If you are saying that an edge has not been sharpened properly until the metal at its very edge has been touched and thus deformed (at least on a microscopic level) then I agree. A burr does not have to be large enough for unaided detection for a knife to be properly sharpened, however.
 
marvinstarving said:
It is still confusing me that one knife burrs and another won’t.
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Burrs are usually caused by deformation in steel, where the steel is too soft for the grindability. In some cases however it is simple because the edge is too thick and you are not even reaching it just grinding above it. Just lightly put a small flat on the edge and see if it is removed when you hone.

Buck268 said:
Allan, thats just not right. Then you end up with this mans very problem to begin with- an off-center edge! Maybe not every time, but you could easily end up removing much more material from one side then the other.
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No, that is a myth, progated by some, some trivial math shows it to be false. In your case the edge did burr, you were just unable to detect it. If you viewed it under magnfication you would see it clearly, 10X is enough. Even a strong light will show even minute burrs readily due to shadows.


Allan Molstad said:
Knife makers are the guys who are able to take a blade that has never been sharpened before, and turn it into a edge that will shave hair.
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This has little to do with knife making. I have been measuring sharpness for a long time, in general the knives that Spyderco sells are sharper than the vast majority of custom knives and the guys who sharpen them are not knifemakers.

But as far as I have seen, the more websites I visit and read on this topic, the more knifemakers I talk to or read their books about it, and the more people that sharpen knives for a living, all....all seem to say the very same thing about how truly important the burr is.
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Yes, that is a lot of wrong people. It is unfortunate that people misunderstood what guys like Talmadge wrote. The burr has only one purpose, it shows you when you have OVERSHARPENED. Consequently logic dictates with proper methods you don't form a burr. Of course on some steels this is fairly difficult as they are too soft for the carbide content.

-Cliff
 
I personally try to avoid burrs like the plague, and when I started following Cliff's advice of cutting straight into the stone prior to sharpening and using magnification for visual verification my edges got much cleaner and sharper. If you cut lightly into the stone to make the knife dead dull, you will know you have gone far enough when it is sharp, prefererably without forming a burr to go along with your aligned edge. I use a Radio Shack lighted microscope that works very well for looking at the edge condition, and that along with practice allows me to sharpen without bringing out a big burr that I have to get rid of, though I still end up dealing with tiny burrs usually. When I do deal with burrs, I usually use Jeff Clark's method of raising the angle for a few light passes until the burr is gone, which is a step back instead of forward in terms of sharpening the blade, but very neccesary when a burr pops up. If I could get a mythical burr free steel my life would be much easier, as basically my sharpening is minimizing any burr I create. I hear that high hardness, low carbide steels may be the closest thing going to that mythical burr free steel, unfortunately I don't currently have anything of that steel class right now. With some steels like my CRKT's AUS 6 & 8 I get extremely frustrated because all I am doing is trying to get rid of the stubborn, flip flopping burr those softies create, and a lot of the times I end up cutting into the stone and starting over because the burr just won't go away. I think the use of microbevels is very helpful in reducing burrs also, as you abrade so little steel that you deal with much less burring than full bevel sharpening, and they definately speed up the process.

Mike
 
Cliff Stamp said:
Yes, that is a lot of wrong people. -Cliff
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Im interested , Im always interested in learning about new views. Can you point me to a knife maker that has written in support of your, "views"?

There are many knife sharpening companies around, many must have a "How to Sharpen a Knife" website, perhaps you would list the address so I can read up some more on this topic?

I have been reading a lot about sharpening, and I find agreement as to how it's best done right. I have yet to read one word in support of this idea that "burr is bad"...

I base a lot of what I know about sharpening on the work of guys like John Juranitch who do this for a living, http://users.ameritech.net/knives/Juranitch1977Feb.htm
May I quote Mr Juranitch?
"Fold the paper again and you get 11 degrees. This is the angle you should use with the coarse hone for the secondary edge. Use whichever motion you prefer, back and forth or circular, being very careful to hold the angle constant. If you have trouble knowing when the burr forms (see diagram next page), check with a magnifying glass; once you see that curl you'll learn to feel it with your fingernail."

This is the very same system I have talked about here.
I am not going around inventing my own system, I try to support what I have talked about here as best I could, not with my own "personal stories" but rather with the words of experts in the field or guys who have took the time to learn about what they are talking about
http://mse.iastate.edu/fileadmin/www.mse.iastate.edu/static/files/verhoeven/KnifeShExps.pdf
So if there is a different system that some claim is better, then I would like to know, "Who say so?"
 
Allan Molstad said:
Can you point me to a knife maker that has written in support of your, "views"?
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Science don't care WHO says something rather WHAT is said. I deal with logic, facts, measurements, not views/opinions. Explaining why a burr is not necessary is a matter of simple math/physics as noted in the above.

Yes I am aware of Verhoevens work, I have corrosponded with him personally. Note Verhoeven doesn't use the term burr the same as it is on the forum. Specifically he defines it as the physical extent of the non-zero intersection of the edge apex.

At a minimum, the edge will still be at about 0.1 micron wide due to limitations on physical structures in the steel. At this level of sharpness Verhoven would define the steel to still have a burr, but everyone else would consider it deburred.

May I quote Mr Juranitch?
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Not a good idea beyond novice level.

gunmike1 said:
With some steels like my CRKT's AUS 6 & 8 I get extremely frustrated because all I am doing is trying to get rid of the stubborn, flip flopping burr those softies create, and a lot of the times I end up cutting into the stone and starting over because the burr just won't go away.
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Don't blame the steel, blame the manufacturers. Those steels are actually among the easiest to sharpen when properly hardened, unfortunately this isn't the case. They are inexpensive steels and given inexpensive heat treatments. The same thing happened to 13C26 which is why it was wrote off as low 440 class for a long time. 1095 gets a name as a beater steel for the exact same reason. But harden it to 66 HRC, grind it thin and now take a look at it.

-Cliff
 
Say CS.
Im still looking for the name of a well known author or a bladesmith, or a guy who sharpens knives as his job, that supports this idea that "bur is bad"

There must be one website right?

(it's a big internet.....)


or....is this all just Cliff's idea?
 
I didn't origionate that perspective, I read it from Ben Dale. Since you continue to ignore facts and logic and want blind faith in names then this discussion isn't productive.

-Cliff
 
My knives are all sharper than when they were new as well as being sharper than those of any edges i've felt that were sharpened by "professional sharpeners". So what? Some of these "professionally sharpened" edges were handed back to me with ultra weak razor sharp burs still attached. As normally used here, a bur has nothing to do with a perfect edge. A perfect edge is one whose planes intersect at zero thickness. You dont have to create a detectable bur to achieve this. Names mean zilch. Show me the research.
 
WOW! All the guy is asking for is some type of document, or web page supporting the burrless method so he can learn more about it. Excepting a post or two of Cliffs argumentative posts would be blind faith, not the other way around.
 
The bur is key to getting a knife sharp.

Think of the bur as being a guest to your house for the weekend.

You plan ahead for the guest
You get everything set so that the guest has no trouble getting there.
When you see the guest appear and you are very happy.
Not as happy as you are to see him go however.

The bur is much like the guest in my example.
You plan for the bur, and get everything all lined up so to make it easy for the bur to show up on the edge of your knife.
But the moment you get a nice bur, you got to start to get rid of that bur.

A bur left on a knife is bad news.
All of the next stage sharpening, (the traditional stroke-flip-stroke) is aimed at getting rid of that darn bur.

the last few strokes of the blade across the stone are very light, with a greater angle, just to make sure you got as much of the bur off the edge of the knife, without starting another one!

The experiments on edges that I posted a link to is all about how to get rid of the bur once it has finished it's job.
The very best system they listed for getting the smallest bur leftover is Japanese water stone and a leather strop with buffing compond on it.
 
Cliff Stamp said:
Don't blame the steel, blame the manufacturers. Those steels are actually among the easiest to sharpen when properly hardened, unfortunately this isn't the case. They are inexpensive steels and given inexpensive heat treatments. The same thing happened to 13C26 which is why it was wrote off as low 440 class for a long time. 1095 gets a name as a beater steel for the exact same reason. But harden it to 66 HRC, grind it thin and now take a look at it.

-Cliff
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That is why I threw in "softies" when describing those steels and mentioned the manufacturer. From what I have heard Benchmade's AUS 8 acts much better being run several points harder than CRK&T does, but I haven't personally had a chance to work with it. From what I have read Alvin's 1095 at the hardness you mentioned is really great stuff, maybe one day I'll get my hands on it. In the meanwhile the only thing I get to play with in that hardness range is ZDP 189, which of course is off the charts in carbides, but still works very well for me, presumably due to it's hardness.

Mike
 
db: I certainly don't mean to come off as a jerk. Just trying to get the point across that a sharp knife is a sharp knife whether you make and remove burs or go straight to a refined edge. I am not advocating either method over the other as i have gotten equally sharp edges using both methods.

Allan: Although cliff does indeed have a cat named Ben Dale, I am pretty sure he was referring to the Ben Dale of edge pro who by all accounts can make a very sharp edge. The instructions he has posted on his website include the raising and removal of a bur as an indicator of satisfactory sharpening. I haven't read verhoevens whole report but i dont think that it is really about the removal of a bur as we define it. It was more an evaluation of a few processes and tools and how they compare in finish and how refined the edge actually is. Anecdotally, when i use my 4k/8k norton waterstone i never get a detectable bur but my sharpest knives are usually done with it. Perhaps that would be more akin to the sexy houseguest who cooks and cleans while you watch tv.:D
 
Allan Molstad said:
A bur left on a knife is bad news.
All of the next stage sharpening, (the traditional stroke-flip-stroke) is aimed at getting rid of that darn bur.

the last few strokes of the blade across the stone are very light, with a greater angle, just to make sure you got as much of the bur off the edge of the knife, without starting another one!

The experiments on edges that I posted a link to is all about how to get rid of the bur once it has finished it's job.
The very best system they listed for getting the smallest bur leftover is Japanese water stone and a leather strop with buffing compond on it.
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I've been thinking about this a lot today. At first I was thinking that if you just did a stroke on each side, eventually you would get to the razor sharp hair poppin' edge that so many of us crave.

My question to Cliff or any other fans of the burrless method is this: If you don't develop a detectable burr, isn't it easier to leave a sharp tiny burr on the edge? Normaly I would take a few passes at a higher angle to get rid of this, but if it's not detectable... do you just take care of this with a strop/steel/hone?
 
pablo486: Well, if you dont make a burr you cant leave one behind. A more practical answer though is that when im sharpening on waterstones the bur is constantly being removed which is why it doesnt form a big narly wire edge. I dont increase the angle of the blade for the last few strokes but i do decrease pressure and alternate sides while tapering off number of strokes per side. Even on a relatively soft 440a leek I dont have a problem with an invisible wire, it remains sharp until excessive abrasion or deformation requires a touch up.
 
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