Best ways to manage burrs during sharpening

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maximus83

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Nov 7, 2011
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Looking for ideas on best practices for working with burrs during sharpening. As usual, seeking the simplest, most streamlined approach that works. The approach I'm using I don't intentionally create burrs, but in some cases getting that as a side-effect when I reprofile a blade, then found it was hard to get rid of it and get the blade to a final level of sharpness.

Here's what I observed:
  • During the scrubbing action of profiling a new/cheap and very thick 1095 blade, it took a lot of scrubbing, and a large tough burr was created.
  • Tried a few slices at the same bevel angle on the coarse stone, wouldn't even put a dent in it!
  • Finally tried something I've seen here in a few forum videos, it took 3 or 4 high-angle (like 30 dps) slices to grind it off.
  • Then had to return to more profiling to fix the effect of grinding off the large burr.
  • This large, thick burr kept popping up repeatedly throughout the profiling. So I kept alternating by grinding it off, then profile more, then rinse and repeat.
  • Finally got the worst of the burr gone and a decent edge bevel, then went to slices on a finer grit and got it sharp in the end.

Questions for future practice:
  • Is this normal or should I have done something different to manage the burr? For instance, alternate sides more frequently during profiling and maybe reduce the occurrence of burrs in the first place?
  • Is high-angle slices (higher by 10 to 15 dps than your edge) the best and simplest way to grind off the burr, once you have one?
  • Is some kind of stropping the best way to finally reduce the small burr on your refined edge, for example, using HeavyHanded's method of wrapping paper around your coarse stone? Or again, maybe just a couple of VERY light stroke, high angle slices on your finishing stone?
 
Watch more closely for the very beginning stages of the burr formation. Burrs only get very large if they're not noticed soon enough. Also, as you get closer to apexing during the grinding (scrubbing) stages, ease off the pressure a bit (or maybe a lot, depending on how much pressure you're already applying), and stop & look for the beginning of the burr more frequently. When you detect even a partial burr along only a small segment of the edge, that's a strong sign to ease up and watch more closely for the burr to form on the rest of the edge. Odds are, the burr will start in a narrow segment and then expand across a wider span of the edge from there. As you see that happening, you want to bias your pressure and heaviest grinding in areas AWAY FROM the expanding burr, and toward areas where it hasn't started forming yet.

If the burr is REALLY HUGE and very tough at the same time, i.e., it's stiff and not easy to break off, that's a strong sign that you've gone too far without noticing it forming AND the pressure has been much, much too heavy. Going too far widens the burr, and too-heavy pressure effectively thickens it, as the pressure tends to make the edge/burr roll over before it's been made thin enough to easily break away.

It is possible to go too far and make a wide burr, while not using too much pressure, and the result is a very delicate, feathery burr that can be broken off just by rubbing the edge across your fingertip. If you see that, it's just a matter of paying closer attention to when the burr starts to form, and catching it earlier. I mention this, because I've done it, and didn't recognize what I was looking at when I saw a very, very thin sliver of steel come off on my fingertip, when I was feeling the edge for sharpness. That was my first introduction to the burr, a while back. ;)


David
 
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This^
As you are working, switch sides. Once you feel the burr form you should commence beating it back with a few very light high angle swipes just where it is forming.

When working a knife from the factory the edge will be uneven and the burr will not form evenly. You do not want to let it get big or too uneven, and you don't want to flip it too many times either.

High angle slices are the best way to grind it off. You can also backdrag the edge at 90° to a piece of hardwood or similar and make the burr stand up a little higher - this also makes it easier to remove the bur with higher angle or same angle passes.

Stop and inspect often - inspect after every high angle pass. Once the burr is gone, drop back down to the original angle and finish with a couple of light passes. Inspect for burrs.

When I am working I am constantly checking for burrs and three finger sticky as I go. A paper strop, loaded strop, dragging through wood etc all will only work on the smallest of burrs.

The attachment point on the burr gets weaker with every flip, once it forms use very light pressure and try to reduce it as much as possible without flipping it. Is OK if it does, as long as it gets a lot smaller every flip.

Softer stones that make some mud will generate smaller burrs.
 
Slurry-forming stones will generally do a good job of preventing burr formation. If you end up with a really thick one and the stone being used is fine the slurry can have a hard time cutting the burr off, but as long as the pre-existing burr isn't super stout then usually a slurry-forming stone will cut off the burr nicely for you. That same quality can make finishing using edge-leading strokes difficult. In the case of your Arctic Fox stone, use it saturated with moderate pressure to generate a slurry, then do your final passes with the slurry rinsed off and no water actively pooled on the surface, using light strokes.
 
OK this all makes sense. So condensing:

  • Inspect more often while profiling and deal with burrs immediately when they form.
  • Change sides more often.
  • High angle slices are the best way to deal with a burr that has already formed.
  • When using a slurry-forming stone like AF to finish: leveraging the built-in slurry will reduce the amount of burr formation.
 
I debur during my sharpening stages with a fine stone in a stropping motion.
 
maximus83 said:
OK this all makes sense. So condensing:

  • Inspect more often while profiling and deal with burrs immediately when they form.
  • Change sides more often.
  • High angle slices are the best way to deal with a burr that has already formed.
  • When using a slurry-forming stone like AF to finish: leveraging the built-in slurry will reduce the amount of burr formation.
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In a nutshell, yeah. :)
 
Forty two, I'm still favoring my minimalist approach and keeping it to two stones. But....do you think your fancy new Ptarmigan stone would help me finish SIGNIFICANTLY faster versus needing to take many slices on the AF?

I'm just realizing how much I have to learn about stone materials, once I moved outside of diamond-based like DMT. Those suckers are great and still will use them, but they are also so hard and kind of unique in the way they work, I'm realizing that they kept me from learning other common sharpening things, and I've just never had to deal much with some of these issues like large burrs, thinking about slurry on the stone and actually leveraging that as PART of the sharpening process, etc.
 
The Ptarmigan would go slower. It's only 3µ rather than 22µ. You are jumping from an extra-coarse stone straight to a fine stone, so that's probably where most of the issue is, and adding a stone that's even finer probably won't assist much--it'll just give you a more polished edge with less tooth. So better for push cuts, but not as good with slicing.
 
One of the best ways to avoid problems with burs is to focus on steel that is quite hard and high quality and leaning toward non stainless. The softer, the more stainless and generally but not always the lower price it is the more the bur just hangs on and hangs on.

This will sound stupid but it is true to a good degree : Use stones that the particular steel likes or said another way use stones that are engineered for the type of steel you are working with.

OH BOY OH BOY a good reason to buy more stones and stuff.
 
maximus83 said:
I'm just realizing how much I have to learn about stone materials, once I moved outside of diamond-based like DMT. Those suckers are great and still will use them, but they are also so hard and kind of unique in the way they work, I'm realizing that they kept me from learning other common sharpening things, and I've just never had to deal much with some of these issues like large burrs, thinking about slurry on the stone and actually leveraging that as PART of the sharpening process, etc.
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^^^ This. I usually bypass threads which deal with burrs as I have rarely noted their development on slurry stones. FYI, you can always dope your DMT with SiC powder to emulate a slurry, though the plate will have to be redoped after every unloading.
 
Hi,
adamlau said:
^^^ This. I usually bypass threads which deal with burrs as I have rarely noted their development on slurry stones. FYI, you can always dope your DMT with SiC powder to emulate a slurry, though the plate will have to be redoped after every unloading.
Click to expand...
Thats a good way to ruin a diamond plate
 
Absolutely possible. Particularly if the SiC grit is too low and the size of the largest SiC particle(s) begins to abrade the nickel coating of the steel plate. Doping a DMT Coarse (45u) with SiC #500 where the largest particle allowed is 40u should only result in premature wear as opposed to premature plate failure. Though admittedly, I am not quite as conservative and dope with SiC just under the micron rating of a plate.
 
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I just sharpened today one of my ZDP-189 blades (Endura 4). Used my Edge Pro Apex with Shapton Glass stones.
Hair whittling.
Bur ? What bur ?
Good steel VERY HARD . . . no probs.
. . . no slurry. I HATE slurry. Wash it off as soon as if forms. Nasty time wasting stuff.
 
adamlau said:
Absolutely possible. Particularly if the SiC grit is too low and the size of the largest SiC particle(s) begins to abrade the nickel coating of the steel plate. Doping a DMT Coarse (45u) with SiC #500 where the largest particle allowed is 40u should only result in premature wear as opposed to premature plate failure. Though admittedly, I am not quite as conservative and dope with SiC just under the micron rating of a plate.
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I've tried this and it did give good results.
I stopped as I did expect it to prematurely wear away the nickel. This was pointed out to me by a friend actually, but passes the common sense test.

I suspect it would take a long time in practice to see any harm. I've lapped SIC stones a number of times with diamond plates and no problems.
 
I'm scratching my head, thinking, why add SiC slurry to a diamond stone? I may have not had enough coffee yet. Perhaps to get a different edge.? For damage to occur would take some time. DM
 
David Martin said:
I'm scratching my head, thinking, why add SiC slurry to a diamond stone? I may have not had enough coffee yet. Perhaps to get a different edge.? For damage to occur would take some time. DM
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Same reaction here. And I also read of this a couple of hours ago, as I was just sipping my first taste of coffee for the day. :)

If heavy, tough-to-remove burrs are an issue on a diamond hone, then lighter touch, lighter touch, lighter touch will cure it. The diamond will still cut well at a featherlight touch, without all the burring issues. And barring that, a few light passes on a hard strop (denim is great for this) with the same grit should take care of it, without risking damage to the plates.


David
 
It helps a lot when using diamond plates on cheaper gummy stainless, greatly reduced tendency to burr.

It also works a lot better when doing broad beveled edges/surface work. And it absolutely prevents even a hint of loading.
 
HeavyHanded said:
It helps a lot when using diamond plates on cheaper gummy stainless, greatly reduced tendency to burr.

It also works a lot better when doing broad beveled edges/surface work. And it absolutely prevents even a hint of loading.
Click to expand...

I was just surprised to hear of such a method.

The issue with burring on gummy stainless is real. But I've dealt with that just in lightening my touch on the hones, in the finishing passes, as if brushing dust from the hone's surface. I finish blades in 420HC (Case, Buck), 440A and Victorinox's stainless like that, with just a 'brushing' pass on the hone. Any remnants of burrs left are light enough to be removed on my bare leather belt (sueded side), for a strop. And for loading issues, I've quelled that with just a bit of mineral oil on the hones, which essentially eliminated that issue for me.


David
 
I read that we must remove the burr with the same stone that we used to form it and with leading strokes to avoid break the very edge where one side is the burr and other is the edge. So light-very light-very very light strokes is my advice. I had problem when using diamond stone on soft (I guess is soft because I don’t know the steel) kitchen steel. I was fighting and couldn’t deburr. Even with very very light strokes sometimes is difficult to remove it at all. When it happen I jump to next stone and start build with finer grit until feel the burr again and see lower uniform scratches... I usually like tooth edges at 600 grit so when I go beyond I use 1000~1200 grit and strop to remove the burr again. I never a let a large burr ever a small one or no one. Even at 600 grit my procedure is the same I have to unfeel or less possible feel the burr before strop.
When I can’t fell the burr with my fingers I use a cotton swab. So any micro burr is easy to detect.
 
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