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View Full Version : Please explain advanced deburring - detection of subtle burrs and how to get rid of them



Flounce
04-17-2011, 02:03 AM
I have a sense that I may not be properly deburring. To explain:

I am a relative newbie but have read a lot over the past months and sharpened a number of knives (mine, family, friends) on 500 Beston, 1200 bester, 5000 Rika, 10K naniwa superstone, followed stropping on polycrystalline diamond-impregnated leather.

I do standard deburring by ending on each stone with a edge-trailing swipe of each side, following by cutting 2 or 3 times into a felt pad, before proceeding onto the next stone. On the final stone, my 10K, I go strop and then come back to the 10K to touch up. All this is based on stuff I read online.

I can definitely detect the burr on the more coarse stones, but it gets harder and harder for me to detect as I go up in grit. After finishing on the 5K or 10K where I'm using very light pressure as I go back and forth, detecting the burr is difficult for me. I know I'm sharpening the edge and not the shoulder mostly by the way it sounds on the stone.

So deburring seems simple to me. Yet I've been told by veterans on knifeforums.com that deburring on certain knives, including my Global G-2, can be very difficult and even annoying. I never thought I had trouble deburring, so it raises the suspicion in my mind that maybe there is still a burr on the knives I sharpen, i.e. I just can't detect it.

So my questions, after a very long preface:

- how do I know if I'm successful in removing the burr, i.e. if I can't feel it with my fingers?
- is my deburr technique proper and sufficient?
- if not, what can do I deburr?

THANK YOU!

UglyJoe
04-17-2011, 02:37 AM
I think what they might be talking about, and what you are talking about isn't burr removal, but removal of the mythic wire edge. Dave would have a lot more to say about this than me, because I'm not sure I've ever been truly successful in removing the wire edge without micro-beveling. What I would tell you is that if your edges are holding up as long as you feel like they should be, don't worry too much about it. If you are experiencing what seems to be early edge failure, then you've probably removed the bur, but you might still have a wire edge. The easy way to get rid of that is to micro-bevel on your finest stone, but that is at the cost of having the sharpest possible edge.

iceman01
04-17-2011, 05:04 AM
I discussed this with Dave some month back, he told me that over the years he developed the ability to feel burrs even from high grit stones. I have the god-given talent to feel even the burr created by the 12k SS, so I can not tell you how to detect it using other methods.
Dave told me that his ultimate weapon is to deburr, by felt, wood, cork or what else, after each successive stone. Using this approach I never had problems with bitchy burrs on my Global G-2. To me the "micro bevel on highest grit stone" approach that Jon introduced is a good way as it let's you get rid of the micro burr, decreases sharpness slightly but adds some strength to the edge.

mikemac
04-17-2011, 10:52 AM
Magnification is going to help at every level of sharpening, so add one of those $10 loupes to your kit annd checl your work along the way. If you've been successful at de-burring at 500 and 1.2k, it won't be an issue on the next stones, especially with better quailty steels. So it comes down to 'foundation' work on the 500 and 1.2
After deburring, go back and do multiple trailing edge passes on one side, and see how quickly and how large the burr is if it comes back. If you haven't done a good job at burr removal or have the wire edge, it should come back fast and feel pretty large. If you have a tough burr, or the wire edge, you'll have to flip it back and forth a number of times before it will let go.

Personally, after raising a burr on both sides, I'll do a trailing edge countdown (c-dawg style?), i.e 6 strokes on the front, 5 on the back, 4 on the front, etc until I get to 1,1,1,1,1 - then I'll de burr on fely, then go back and do alternating side countdown again, but maybe with a lot less pressure.

Eamon Burke
04-17-2011, 01:42 PM
My method:

When you finish, cut some paper and a tomato. Then slam the knife edge-first on a cutting board. Then slice the paper and tomato again. It won't be as sharp as before, but if it seems dull like before you sharpened, it's a honking wire edge.

SpikeC
04-17-2011, 01:51 PM
I have always thought that a burr was the same as a wire edge. What is the difference?

Cadillac J
04-17-2011, 02:28 PM
They are pretty much one in the same, as a wire edge is that bit of weakened metal that will remain behind if not taken care of...it can feel sharp, but won't last long at all.

I've used Dave's felt w/ diamond spray for over a year now, and to me it is the ultimate burr removal tool. Between each stone I cut into the felt a few times, then power strop on the felt, then cut a few more times. I've never had an edge fail using this method.

Eamon Burke
04-17-2011, 02:34 PM
A wire edge is a knife sharpening term, a burr is a metal deformation, and the concept is universal throughout all metal-working trades.

I've always considered knife burrs to be spots of bent steel from damage/inaccurate sharpening. A wire edge is a burr consistent enough to cut with, but it is weak, because it is just a straightened out burr, and not a continuation of the structure supported by the rest of the blade/bevels.

UglyJoe
04-17-2011, 03:18 PM
A wire edge is a knife sharpening term, a burr is a metal deformation, and the concept is universal throughout all metal-working trades.

I've always considered knife burrs to be spots of bent steel from damage/inaccurate sharpening. A wire edge is a burr consistent enough to cut with, but it is weak, because it is just a straightened out burr, and not a continuation of the structure supported by the rest of the blade/bevels.

Basically this; I've always thought of "burrs" as loosely held metal that's not consistently attached across all of the edge. It's almost like shreds of steel that are holding on "by a thread" so to speak. Pulling the edge through cork/hardfelt/etc. will pull this deformation off pretty easily. However, with tough steel and working at a shallow angle especially, you can (and will) form a very thin and ultimately week layer of steel just in front of the edge. Unlike what I consider burrs, this "edge" is consistently attached across the whole edge of the blade, and simply pulling through cork, etc. will not remove it. It has to be abraded away. When you add a micro bevel, especially at a higher angle like Jon advocates in a lot of cases, it's kind of like folding a piece of paper across a tabletop edge and then tearing it off. This does remove the wire edge, but also it means the final edge of the knife isn't as acute as it can be. Some people are morally opposed to this, and if that's the case with you, you need to experiment with ways of telling that you have a wire edge and that what you are doing to get rid of it is actually working.

The frustrating thing for a lot of sharpeners is that I really think you only start to get a wire edge when you are working with good steel and your technique is well developed. With weaker steel and/or wobbly technique, I think you tend to form burrs mostly and very little wire edge. Especially with wobbly technique, as your edge angle isn't consistent enough to get that one smooth consistent strip of steel that is the wire edge. I think it frustrates a lot of sharpeners, because they start off with cheaper steel, they work with wobbly technique, and they achieve an okay edge after they finish - an edge that I and many others thought was wonderful because we had never really felt a great edge before. You then get better knives with better steel, your technique improves, and suddenly you start generating wire edges that are sharp as a mother, but the edge fails after a few sessions cutting with the knife, and you begin to be upset, thinking that you suck at sharpening or that the knife you spent a lot of money on sucks, etc.

Wire edge removal is the hurdle that moves you from beginner sharpener to good sharpener. Once you learn it well, you'll see a dramatic increase in your edge quality and endurance.

heirkb
04-17-2011, 04:09 PM
Wire edge removal is the hurdle that moves you from beginner sharpener to good sharpener. Once you learn it well, you'll see a dramatic increase in your edge quality and endurance.

Is the removal of a wire edge only possible with a microbevel then?

iceman01
04-17-2011, 04:15 PM
Is the removal of a wire edge only possible with a microbevel then?

Yes, it is. But you have to increase the angle enough to break the wire edge off. In some cases you can even see this thin strip of metal breaking off the edge.

heirkb
04-17-2011, 04:22 PM
Yes, it is. But you have to increase the angle enough to break the wire edge off. In some cases you can even see this thin strip of metal breaking off the edge.

Then the microbevel is the only way? I can see how my question may have seemed like I was asking if it was possible at all, but I was asking if it's the only way possible. I might be misreading your post, though.

Dave Martell
04-17-2011, 04:26 PM
The most effective, yet time consuming, way to rid an edge of the wire is to abrade it away through polishing. You have to remove all loose burrs at each grit level first though. So you draw the loose burrs away and off of the edge by running the edge through something self-healing like rubber or felt and then the wire edge can be abraded away by the next higher grit stone and so on. Sometimes it helps to strop between each stone as well. Keep in mind though that after you strop the edge will likely cut paper well as you've aligned the wire straight but it will fail quick upon board work.

Eamon Burke
04-17-2011, 05:11 PM
+1 on what Dave said. That is essentially the concepts used in straight razor sharpening, where you want the finest edge possible and the least amount of edge abuse in the process.

Micro bevels are a good idea, though, especially for kitchen knives--once we are safely in the arena of sharp knives, kitchen knives need durability first and foremost.

heirkb
04-17-2011, 06:49 PM
The most effective, yet time consuming, way to rid an edge of the wire is to abrade it away through polishing. You have to remove all loose burrs at each grit level first though. So you draw the loose burrs away and off of the edge by running the edge through something self-healing like rubber or felt and then the wire edge can be abraded away by the next higher grit stone and so on. Sometimes it helps to strop between each stone as well. Keep in mind though that after you strop the edge will likely cut paper well as you've aligned the wire straight but it will fail quick upon board work.

Thanks for the help. So if I understand this correctly, the next stone up will remove the wire edge of the stone before and then create one of it's own, right? So what do you do after that last stone/strop in order to remove that final tiny wire edge?

Dave Martell
04-17-2011, 07:57 PM
Nope, the next stone up begins to make the wire edge smaller (not create another one).

The idea is to make it the wire so small that it will not fold under use or so small that we can't tell when it folds as the performance remains high.

Flounce
04-17-2011, 09:46 PM
Thank you all for the informative responses.

I once read on knifeforums.com someone suggest a method where after sharpening on all stones (e.g. 12 degrees on each side), a microbevel (e.g. 18 degrees) is created on one side only with edge-trailing strokes, and then the knife is flipped and an edge-LEADING stroke performed at the same angle as previously sharpened (12 degrees) in order to crush/destroy the burr.

Thoughts on the validity/efficacy of this method?

heirkb
04-17-2011, 10:10 PM
Nope, the next stone up begins to make the wire edge smaller (not create another one).

The idea is to make it the wire so small that it will not fold under use or so small that we can't tell when it folds as the performance remains high.

Thanks again Dave. I think I'm getting it more now.

So in the case of knives that we don't take to a super polish (say we stop at 2-3k or 5k, which is what I was gonna do since I'm a newbie), will there be an issue with the wire edge being too large? I can't tell if that's the case, yet, because I've only been sharpening crappier knives to learn the basics of the technique.

Dave Martell
04-17-2011, 10:24 PM
Thanks again Dave. I think I'm getting it more now.

So in the case of knives that we don't take to a super polish (say we stop at 2-3k or 5k, which is what I was gonna do since I'm a newbie), will there be an issue with the wire edge being too large? I can't tell if that's the case, yet, because I've only been sharpening crappier knives to learn the basics of the technique.


Yeah it might be a problem but the best thing you can do is to try the edge and see how it works.

Dave Martell
04-17-2011, 10:25 PM
Thank you all for the informative responses.

I once read on knifeforums.com someone suggest a method where after sharpening on all stones (e.g. 12 degrees on each side), a microbevel (e.g. 18 degrees) is created on one side only with edge-trailing strokes, and then the knife is flipped and an edge-LEADING stroke performed at the same angle as previously sharpened (12 degrees) in order to crush/destroy the burr.

Thoughts on the validity/efficacy of this method?


I'm sure this can help with burrs but I know it won't do anything for the wire edge except straighten it out.

UglyJoe
04-17-2011, 11:20 PM
I agree with Dave on this one. As I said, wire edge removal is the first really difficult hurdle to overcome as a sharpener. In addition to what Dave said, I feel that sometimes it's useful once you've gone through your stone progression to drop back down a stone or two and lightly strop the knife a couple of times then work back up the stones again, stropping. In principle if you've done a good job making the wire smaller as you've gone up through the stones, then lightly stropping with the lower grit stones should sort of shred what's left of the wire edge and make it more "burr-like". Once you go back up through the progression quickly with a few stropping strokes and deburring you should have a pretty good edge and very little wire left. Dave might disagree with me on this, but I think it's something everyone should experiment with at least a few times to see how it affects your final edge sharpness and, in particular, your final edge's longevity.