Need a burr?

Z

ZtCubster

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Jul 25, 2017
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I am good at freehand sharpening but something I've always wondered was do you need a burr? When i first started I would rotate sides after each pass but now i stay on one side till a burr forms and switch. Then do a few passes alternating between sides before going to the next grit. Anyways is there a difference in the edge when alternating or staying on one side till a burr forms?
 
I always work up a burr on the first side I start on. Flip it over and work up a burr on the other side. Just a slight one. This gives me my base line on the coarse stone and sets my angle. From there on finer stones I'm just refining the edge and reducing the burr. DM
 
For me, I don't chase the burr. I prefer a more durable edge, so I stop at shaving sharpness, and I usually favour alternating strokes.

I have chased the burr a few times. My Spyderco Endura 4 absolutely refused to take on a burr, or maybe it was there but I just couldn't feel it. I got fed up after about an hour or so of futile grinding.

My Ka-Bar BK11 did form a burr and it actually split hair, sharpest knife I've ever done (wonderful steel, this 1095 Cro-Van). Never managed to recreate that sharpness since, and I don't think I'll be putting that edge on my BK11 ever again, BK11 is meant for hard-use, and it should be the BK11 having the durable edge and the Endura 4 splitting hair.
 
As others said you don't need a burr; it is an indication that you have sharpened to the apex. But if you have sharpened to the apex, there will be a burr formed. It's a question of how readily visible is the burr.

I think burr formation depends on a few things including softness of the blade material (the softer the material, the more the burr) and sharpening angle (the smaller the angle, the more the burr).
 
One thing I have been doing more and more of is avoiding an obvious burr at low grit.

When reprofiling an edge I stop as soon as it begins to feel sticky, even a little. Normally not quite to the edge. Then I run all the way to an apex with a medium grit and remove burr on same. This seems to speed up my progressions quite a bit and not hamper a good outcome.
 
HeavyHanded said:
One thing I have been doing more and more of is avoiding an obvious burr at low grit.

When reprofiling an edge I stop as soon as it begins to feel sticky, even a little. Normally not quite to the edge. Then I run all the way to an apex with a medium grit and remove burr on same. This seems to speed up my progressions quite a bit and not hamper a good outcome.
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^This is actually what I've been doing lately as well. I've never really had the illusion that one could do completely burr-less apexing, but I have been trying to aim for burr-minimal apexing, where that goal of keeping it as reduced as possible changes your sharpening process and for me, has enabled me to get to the sharpness level I want with less time and frustration. But I'm learning and trying different approaches as I go, it's fully possible that next week, I'll be into forming epic burrs intentionally and loving it. :D
 
Any of you guys have any videos of " no burr" Sharpening? I want to see how long it takes from a dull, flat plateau edge, maybe chip too. I'd also like to see what level of sharpeness you guys get.

Haven't seen any videos of this yet to judge
I've tried but I didn't get what I was looking for, maybe watching I can see.
 
Good question, I'd be interested to see an e2e video on--I'd prefer to call it--'burr-minimal' sharpening as well, if somebody knows of a good one. Not the Cliff Stamp one that often gets used, it's ok but pretty brief.
 
Didn't take video, but I sharpened a White #2 blade at 220, 1000, 4000, and 0.3 um lapping film, alternating each pass. Didn't check for a burr, and ended up with an edge that would cut a free hair about 0.75" from the point of hold. The hair caught, then cut through. It took a while, maybe 20 minutes. Most of that time was spent swapping my stone holder from left to right.

Total number of passes was about 25 per side on the 220, 40 to 50 per side at 1000, 50 to 60 at 4000, and 30 per side at 0.3 um. The stones were used at 12 degrees per side, and the honing film was freehand at about 15.
 
I just recently started thinking about what I've heard Cliff Stamp say... that a burr is weakened metal. That's hard to disagree with. But it definitely seems like a challenging thing to attain. If I'm not mistaken, I believe his method relies on "destressing" the edge (flattening it with a couple strokes on the stone) and then sharpening with alternating passes and checking regularly for reflection off the destressed edge just until it's gone? It seems like he's a fan of microbevels too, as it sounds like he's all about edge retention and durability. Do I have that right? Does anyone have links to any other burr-less gurus out there?
 
One thing Cliff himself appears not to notice is that most of your cutting performance comes from the geometry of the blade. He notes incredible edge retention and appears to attribute it entirely to the durability enhancement he believes is afforded by not forming burrs and thereby weakening the edge. But really, I suspect his incredible edge retention is almost entire due to the fact that he uses thin blade stock with zero-ground bevels. Of course that's gonna cut like a pissed off demon; I have the shittiest 4" santoku made of garbage steel, but it is one of my best cutters, even though it's dull as all hell, simply because it is already really thin blade stock, and then I zero-ground this weird hollow grind it had, effectively turning it into a wide-bevel knife. Point is: dull apex, yet it still cuts like an angsty teenager due to its incredibly thin geometry.


Anyway, I do agree with many of the previous gentlemen. I believe the formation of a burr is inevitable upon the apexing (that is, sharpening) of an edge. Therefore the game is not to avoid burr formation, but instead to minimize it. Personally, I generate the smallest burrs I can possibly detect on every stone in my selected progression. Helps ease off the work required in stropping
 
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Beansandcarrots said:
One thing Cliff himself appears not to notice is that most of your cutting performance comes from the geometry of the blade. He notes incredible edge retention and appears to attribute it entirely to the durability enhancement he believes is afforded by not forming burrs and thereby weakening the edge. But really, I suspect his incredible edge retention is almost entire due to the fact that he uses thin blade stock with zero-ground bevels. Of course that's gonna cut like a pissed off demon; I have the shittiest 4" santoku made of garbage steel, but it is one of my best cutters, even though it's dull as all hell, simply because it is already really thin blade stock, and then I zero-ground this weird hollow grind it had, effectively turning it into a wide-bevel knife. Point is: dull apex, yet it still cuts like an angsty teenager due to its incredibly thin geometry.
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Hi ,
thats funny stuff :)
but yeah that guy writes a lot of stuff,
its easy to get the wrong impression
unless you read the summaries and watch the videos (summaries)

edge retention is not the same as cutting ability,

so If you likes to read ,

2006 bladeforums/a-model-for-cutting-ability.421313/
2003 bladeforums/geometry-and-proper-sharpening-vs-steel-quality.261961/
sharpening-method-or-blade-steel.1544808/#post-17748979

The Lum for example after cutting ~300 pieces of 1/2" hemp is at about ~1% of sharpness with the highest performing micro-bevel in the above. However at this point due to geometry alone it still cuts 1/2" hemp with < 15 lbs .
 
Beansandcarrots said:
and then I zero-ground this weird hollow grind it had, effectively turning it into a wide-bevel knife. Point is: dull apex, yet it still cuts like an angsty teenager due to its incredibly thin geometry.
Click to expand...

In the videos I've seen, it doesn't appear that he's doing a zero grind (although it does look like he's sharpening at a VERY low angle), then he finishes with a microbevel.

I'm just wondering if this is a realistic way to sharpen. I tried it the other night and felt like I was sharpening blind.
 
DainBramage1 said:
In the videos I've seen, it doesn't appear that he's doing a zero grind (although it does look like he's sharpening at a VERY low angle), then he finishes with a microbevel.

I'm just wondering if this is a realistic way to sharpen. I tried it the other night and felt like I was sharpening blind.
Click to expand...

To a certain degree, I feel it is. An extreme angle, like 10-12dps in my own personal case, with a higher (15dps) microbevel does appear to provide a stable edge (I regularly chop wood with this configuration with no ill effects), but sharpening at too low of an angle makes the strokes somewhat difficult, and a thin shoulder is nice, but you still retain the general geometry of the blade as a whole, so it doesn’t really make a world of difference in performance to the more standard 30 or 40dps edge... at least in my own uses
 
Went back and took a look at the summary for the Lum vg10 test and really could not make sense of the data. A thinner edge corresponded to longer edge retention on rope and sharpness test vs a piece of thread, but the notes also described the edge finish as being increasingly coarse as the angle decreased.

A better test is to cross the amount of weight needed to make a pressurecut vs the amount needed to make a drawing cut at given edge angles. Unfortunately I cannot claim much, having only done a handful of these, so easy to be critical of others work. The hardest two things in any test is uniformity of test media (pressure, cut distance, material qualities), and uniformity/reproducibility(?!) of test conditions (edge finish and angles).

All things being equal, thinner is better up to about 8° per side and then thinner doesn't seem to yield any improvement (assuming a common microbevel. Lateral stability drops way off as angle decreases though, so as always it is important to tailor the edge to the job if possible.

Again, there doesn't seem to be any correlation between retention and burr/burless strategies that I could find, use of a microbevel doesn't assume the absence of a burr and it was otherwise not addressed.
 
In practice, I think that when most people sharpen their knives and use the 'burr method' to determine when to stop and move to the other side, they just end up bending the burr back and forth from one side to the other. As they move to higher grits, the burr gets finer and finer as it gets passed from one side to the other and the end result is that the finished product is just a very sharp wire edge. The burr is never completely removed. It is just so fine that it is not detected by the 'finger method' most people use. Basically, youre sharpening and polishing a burr rather than an edge. The end result is something that dulls extremely quickly once the microburr wire gets ground off from use.
 
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