Is a bur actually needed?

A

asterik216

Joined
Apr 21, 2017
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So I came across Cliff Stamp on YouTube. I would guess most of you know him. Anyways everyone everywhere says you need to develop a bur. It is basically a mandatory part of sharpening. Well according to Cliff that is bad as that is metal that is now weak and you end up with less edge retention. It really does make sense that would be the case. He actually seems like a amazing sharpener and has a lot of contradictory ideas but actually make sense. The guy sharpens holding the stone in one hand and the knife handle in the other and very quickly its super sharp. He just stood out from everyone and seems like he knows quite a lot about all this.
 
Cliff is right--you don't need nor actually want a burr. It's just an easy way to tell that you've fully apexed the edge on that side, but a keen eye looking at your scratch pattern can tell you the same thing without having to create a burr.
 
If you can sharpen with a burr and eliminate it, technically you can sharpen without one. It realistically cannot be done without microbevelling or conceivably a hard strop would fit the bill.

You can also set the bevel on a softer waterstone and grind a new edge with no burr or no appreciable burr and finish on a polishing grade stone without raising a burr.

Getting the edge to the point where the entire edge is ready to be finished so that no bit of it is going to be "crossed" while the rest of it has just reached a fresh apex is going to be quite the trick.

Aside from Cliff, I am not aware of any other person whose testing showed a reduction in edge retention from the creation and elimination of a burr. Virtually all industrial sharpening involves the formation and subsequent clean-up of a burr and many of these blades last incredible numbers of cut cycles.

He also recommends grinding the entire edge off with a medium or coarse stone at the outset (destressing?). How this can somehow cause less subsurface weakening of the steel than the formation/removal of a burr would be tough to explain as the mechanical process is virtually identical.

In my experience there will only be a reduction in edge retention if the burr is not properly removed. If one has trouble removing the burr reliably without creating other issues, by all means give his method a try. There are a number of ways to craft a clean, sharp edge.
 
Like everything I saw from that guy makes sense and seems legit. Also just the way he sharpens holding everything and like he isn't even trying. It makes it hard not to listen to what he says
 
HeavyHanded said:
If you can sharpen with a burr and eliminate it, technically you can sharpen without one. It realistically cannot be done without microbevelling or conceivably a hard strop would fit the bill.

You can also set the bevel on a softer waterstone and grind a new edge with no burr or no appreciable burr and finish on a polishing grade stone without raising a burr.

Getting the edge to the point where the entire edge is ready to be finished so that no bit of it is going to be "crossed" while the rest of it has just reached a fresh apex is going to be quite the trick.

Aside from Cliff, I am not aware of any other person whose testing showed a reduction in edge retention from the creation and elimination of a burr. Virtually all industrial sharpening involves the formation and subsequent clean-up of a burr and many of these blades last incredible numbers of cut cycles.

He also recommends grinding the entire edge off with a medium or coarse stone at the outset (destressing?). How this can somehow cause less subsurface weakening of the steel than the formation/removal of a burr would be tough to explain as the mechanical process is virtually identical.

In my experience there will only be a reduction in edge retention if the burr is not properly removed. If one has trouble removing the burr reliably without creating other issues, by all means give his method a try. There are a number of ways to craft a clean, sharp edge.
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He did run the edges along the stone in his videos. I could theorize why that might be ok. You would have removed some of the metal that might have been stressed and will actually end up being part of your edge. Also maybe it give you a some even and fresh edge to start on so it is more uniform. I obviously can't say for sure. I just started messing with sharpening
 
asterik216 said:
He did run the edges along the stone in his videos. I could theorize why that might be ok. You would have removed some of the metal that might have been stressed and will actually end up being part of your edge. Also maybe it give you a some even and fresh edge to start on so it is more uniform. I obviously can't say for sure. I just started messing with sharpening
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The edge has already been worn off in the most gentle fashion imaginable - slow dulling from use. A dull edge doesn't just flop over and/or get pushed back into the bevel, it actually wears away and is gone. What's left is going to be more structurally sound than anything (theoretically) you'll have left over from the grinding process. Brent Beach does a good job of explaining it:

http://www3.telus.net/BrentBeach/Sharpen/jig faq 02.html#thebest

Unless you have been cutting very hard items, there are no stresses in the steel that need removing. I suspect it is done more to set the edge up so there is a visible flat along the edge that makes the "plateau" method easier to use, rather than for any crystal matrix reasons.

It remains to be convincingly proven that any of these effects make a practical difference one way or the other, as there are always a handful of variables when doing retention testing. Geometry normally trumps everything else.


asterik216 said:
Like everything I saw from that guy makes sense and seems legit. Also just the way he sharpens holding everything and like he isn't even trying. It makes it hard not to listen to what he says
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He knows how to sharpen, but again, there are many ways to get a sharp edge - give it a try.
 
Lately I've been using a lot of my Spyderco ( ceramic) stones to do most of my sharpening. I just had shoulder surgery so I have to use the 204 Sharpmaker clamped down and using one hand. But I've found by using this tool with very fine grits and by alternating each side on each stroke that I don't get a "burr". Or it's so small I don't even realize it. Now I do still play with strops a little after using the stones. I've got a strop made of "Russian Boar" hide that I got from a "Barber Supply" house some time back and it seems to be a bit better than your average leather strop IMO.

Now on chisel edged tools like plane blades and other woodworking tools I don't see how you could avoid a burr? But on any knife where you stroke it alternating both sides I think you can use very fine stones and avoid it with decent success IMO.
 
I only bought this up because it was so much different then everyone and lots of it seems reasonable. Like for example flattening waterstones. I guess some say you shouldn't.
 
When sharpening lower RC stainless and carbon steel I prefer my Norton waterstones. The 1k is pretty soft, so lots of lapping action.
I just grind till the edge gets "sticky", as in most cases it won't raise a visible burr.

I normally do this with all my stones and wet/dry, but with harder stones there is normally a small burr forming concurrent with the edge becoming sticky. Not mandatory, but not unexpected or detrimental either.

In all reality, the burr is metal outside the geometry of the edge. Remove it to its attachment point and its gone.
 
asterik216 said:
I only bought this up because it was so much different then everyone and lots of it seems reasonable. Like for example flattening waterstones. I guess some say you shouldn't.
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It is good practice to flatten them, but you can go a long way by just moving around on the stone religiously. As long as you are moving around on the stone, any low spots aren't going to hit in the same place every time and it will have no cumulative effect on the edge geometry. If you hang out in one spot and grind a dish or groove, you'll have trouble.

Normally I just leave them a little dirty when I'm done, next time I go to use them I'll pass a flattening stone across the surface a few time and wherever it cleans up first (highest spots) is where I'll start my grinding on the next job. The never really get out of flat.
 
What about rubbing a rougher stone in a hard oil stone to speed up the process. I thought that wouldnt be a bad idea
 
He was saying something like if your sharpening at 15 dps the humps might actually make it 17 or 18 and when you switch stones your all messed up. Also though that it takes like 5k passes till he does it.
 
He rubbed a 200 grit on a really hard stone that didnt cut cause it was so hard and clogged. It was like using a really hard 200 grit stone and made it cut much faster
 
asterik216 said:
He rubbed a 200 grit on a really hard stone that didnt cut cause it was so hard and clogged. It was like using a really hard 200 grit stone and made it cut much faster
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Ahhh. Yep, that'll work for a few till the texture wears back off or it plugs again. It'll also make the 200 grit stone glaze over unless it's a diamond plate, and now IT won't cut well. You'd need to condition it with something else to make it work like a 200 grit stone again.

Put some coarse lose grit between both with a bunch of water or oil and lap away, you'll recondition both of them at the same time.
 
The raising of a burr is not a problem to be eliminated, it's information from the edge that tells you when the stone has ground off the edge all the way to the apex.

The burr doesn't come up at the exact same time on all parts of the edge because dull edges are not uniformly dull. Some parts of the edge are duller than others, and many parts of the edge will remain sharp because they haven't been used. The sharp parts of the edge will raise a burr right away. The duller parts will take longer. For this reason, the burr will rise up along the sharper parts of the edge first, which is why most experts will advise raising a burr the full length of both sides.

In some cases, you can sharpen without raising a burr -- usually by stropping an already sharp edge. But to sharpen an edge without raising a burr during the normal resharpening a dull edge, you would have to stop sharpening at the exact right moment on each part of the edge, both sides, when the that exact right moment is different along different parts of the edge. If that's possible on a dull edge, it would be a burdensome task.

The only way that raising a burr with hand stones will weaken the edge is if you leave the burr. If you raise a burr the full length of both sides and properly remove the burr, you won't have a weak edge. You'll have a sharp edge.
 
I like to use a 10X magnification eye loop to inspect the edge while sharpening.
Very easy to observe small burrs and for my free hand sharpening, some burrs are local for a short length of the edge and other areas are incomplete apex.
It also shows where you have not reached a true apex along the final edge.

Years ago I attended a woodworking show that had Haroldson Stanley as an exhibitor.
He is the USA distributor for Shapton stones and I requested he sharpen my Benchmade 812, I really wanted to see his technique.

He explained burr formation and the problems with tearing it away with wood, cork or leather stops.
He also had a USB microscope set up with a computer screen,,, very interesting.
Stanley recommended removing the burr with your finest stone, use very light pressure or no downward force at all,, and run the blade at 90 degrees down the stone for one short stroke,,,, observe the burr or lack of burr.
Then make a few passes with again, very light pressure to further refine the edge at your apex angle.
The torn away burr was easily seen under magnification and cutting away the burr with the stone then further refinement showed nice improvement.

Some recommend as a final step, forming a micro bevel which may or may not remove the burr with abrasive cutting. I believe it just rolls the burr to the opposite side, it becomes smaller and with some steel alloys, very difficult to completely remove all of it.

One technique I like is to charge a hard leather strop with diamonds,, this does cut away the burr and leave a highly polished edge which is somewhat convex.

Cliff Stamp claims the edge has deformation of the steel under the actual apex after use,,, he cuts away that week bond with a few light stokes, 90 degrees, at the beginning of his sharping cycle. The deformed edge is ragged and weak compared to the tougher steel below,,, we are talking of a very small amount of steel removal, not like the YouTube guy that runs his blade down a brick at 90 degrees for 20 stokes, then proceeds to sharpen.

Regards,
FK
 
I have been using the twice the angle and very light edge leading stroke method to remove a bur. It has seemed to work pretty good. Also the guy who does 20 cuts in a brick only does the so the knife edge is completely destroyed for demonstration purposes and testing of stones knives.
 
Yes, I understand the demo with brick concept however, 3-4 stokes on the side of a 400 grit stone will give a nice flat apex to begin the sharpening demo.
A considerable waste of steel with the brick and I always wondered how many beginners followed the pre sharpening brick method?

Regards,
FK
 
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