Checking for a burr/wire edge

Legacy Forum Archive advanced-techniques-and-sharpening-strategies
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Something I have been doing lately to tell if I still have a burr or a wire edge is this… make sure both sides are shaving sharp off of the stones as much as possible. Then remove from vise, and strop on pant leg for about 5 passes per side (pps). Again, check to make sure shaving sharp on both sides.

Then what I will do is strop on one side of the knife (again, on pant leg - no abrasives), no alternating sides this time, about 4 passes or so. Then again check to make sure shaving on both sides.

If it is only shaving on one side at this point then you know you have a wire edge and it’s not a clean fresh apex - i.e. it won’t be as durable of an edge.

2

Im taking it that you have had this happen or you wouldnt be going thru the trouble to test for it? :blink:

If you are down at the hair splitting phase Im guessing the kinda burr you are talking about is tiny tiny kind, not the big ugly visible ones?

I remember there was a thread on here going back n forth about all the ways we could remove a burr while in progression. What are you doing with your micro wire edge if/when detected?

I usually run my edge lightly thru a soft wood just as I am about to finish my stropping, then hit it lightly again to call it a day.

This is an interesting topic! :woohoo:

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[quote quote=“CliffCurry” post=24478]Im taking it that you have had this happen or you wouldnt be going thru the trouble to test for it? :blink:

If you are down at the hair splitting phase Im guessing the kinda burr you are talking about is tiny tiny kind, not the big ugly visible ones?

I remember there was a thread on here going back n forth about all the ways we could remove a burr while in progression. What are you doing with your micro wire edge if/when detected?

I usually run my edge lightly thru a soft wood just as I am about to finish my stropping, then hit it lightly again to call it a day.

This is an interesting topic! :woohoo:[/quote]

Hey Cliff! yeah, it actually happens on almost every knife unless you purpose to correct it. And yes, I am not talking about a burr you can see or feel, it would be on the micro side. I am just either going lighter and lighter edge leading passes, alternating, or I am stropping but I prefer the former.

A side note… you can tell when your stones are getting worn when they can no longer cut this micro burr off and you continually chase it back and forth. That happened to me after about 400 knives and I found it was time for new stones, actually Cliff Stamp had pointed that out as one of the factors.

I do want to try the wood… I do that when I am machine sharpening and chasing huge burrs but haven’t tried it on the micro level yet. But I know this wire edge is there because if it was a clean apex then stropping it one direction on the pant leg shouldn’t affect whether it will shave arm hair any differently - but it will if it’s there :wink:

4

Wait a minute…you still have arm hair? I must be doing something wrong! :silly:

Seriously tho, usually when I take a knife all the way down to .5u lapping film I do a quick & light swipe down the edge in between each grit change. Results under microscope and hair tested good both sides no problem.

Thats my “auto-pilot” method when working down to super fine levels. I know some would agree and some disagree that this is cool but results are always spot on so… :side:

5

I read an article on sharpening chisels and plane blades in Fine Woodworking Magazine wherein the author describes doing the final polishing on a block of hardwood impregnated with polishing compound. He then removes the burr by drawing the edge across the end grain of the same block.

I normally sharpen one side at a time, so of course I raise a dandy of a burr even with the high grits. As I go through the progression the burr shows up under the 'scope as a fine, white line along the apex, which gets thinner with the progression. When I get to the end of the last grit, I do as Josh describes - very light alternating strokes, always edge leading.

6

This appears pretty timely for the discussion: https://scienceofsharp.wordpress.com/2015/10/20/sharpening-with-the-king-1k6k-combination-stone/

I’d like more information, like number of strokes, pressure etc… I’d also love to see him test edge trailing to start and then finishing with a few, light, edge leading strokes with the 6k stone, particularly at a higher angle, without trying to fold over the burr on wood. Then I’d like to see him lower the angle a little and strop the blade.

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[quote quote=“CliffCurry” post=24480]Wait a minute…you still have arm hair? I must be doing something wrong! :silly:

Seriously tho, usually when I take a knife all the way down to .5u lapping film I do a quick & light swipe down the edge in between each grit change. Results under microscope and hair tested good both sides no problem.

Thats my “auto-pilot” method when working down to super fine levels. I know some would agree and some disagree that this is cool but results are always spot on so… :side:[/quote]

I know right :wink: I normally only pop one or two arm hairs off to make sure it’s good, not a whole swipe! lol.

Yeah, I guess I am meaning mainly 1k grit and below… I never check this above that or when I’m mirroring an edge as my final step is stropping which removes the burr through micro convexity anyway.

Try it at about the 1k level and see what you think… I do really wanna try the wood thing though, seems like a lot use it!

[quote quote=“wickededge” post=24482]This appears pretty timely for the discussion: https://scienceofsharp.wordpress.com/2015/10/20/sharpening-with-the-king-1k6k-combination-stone/

I’d like more information, like number of strokes, pressure etc… I’d also love to see him test edge trailing to start and then finishing with a few, light, edge leading strokes with the 6k stone, particularly at a higher angle, without trying to fold over the burr on wood. Then I’d like to see him lower the angle a little and strop the blade.[/quote]

Todd may pop in here as he monitors this forum, however, you can always post in his comments and see if he can provide that data as he is really responsive. haven’t had time to read the article yet but been meaning to!

8

[quote quote=“wickededge” post=24482]This appears pretty timely for the discussion: https://scienceofsharp.wordpress.com/2015/10/20/sharpening-with-the-king-1k6k-combination-stone/

I’d like more information, like number of strokes, pressure etc… I’d also love to see him test edge trailing to start and then finishing with a few, light, edge leading strokes with the 6k stone, particularly at a higher angle, without trying to fold over the burr on wood. Then I’d like to see him lower the angle a little and strop the blade.[/quote]

Oh man, perfect timing. Love his blog and it always leave me asking as many questions as it answers. After he folded the burr that was formed by edge trailing I dont think he did any edge leading strokes to remove the burr in his tests?

The edge leading tests at the beginning were also great, showing the micro chips at the apex instead of the huge smooth foil he later folded. I wonder what a pass thru wood would do to it as you progressed as well?

Man Id give a small puppy to have access to a microscope like this. Its a fiddlers dream to see the results in real time like that. Thanks for sharing!

9

I have used a Felt Deburring Block for the wire edge. has anyone else used?

https://www.youtube.com/watch?v=9aO5QT5FdVo

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Another item that it would be VERY interesting to see the effects of under high magnification… :wink:

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[quote quote=“razoredgeknives” post=24477]…
If it is only shaving on one side at this point then you know you have a wire edge and it’s not a clean fresh apex - i.e. it won’t be as durable of an edge.[/quote]

Will it shave on the side you strop or the side away from the strop?

[quote quote=“wickededge” post=24482]…

I’d like more information, like number of strokes, pressure etc… I’d also love to see him test edge trailing to start and then finishing with a few, light, edge leading strokes with the 6k stone, particularly at a higher angle, without trying to fold over the burr on wood. Then I’d like to see him lower the angle a little and strop the blade.[/quote]

This was done several times on different blades just to confirm that these observations were repeatable. I did vary pressure and number of strokes over those trials and the results were consistent.

On switching from edge trailing to edge leading - the bulk of a large (edge-trailing) burr is usually broken within one or two strokes on the finer stone, but the apex is not clear until we abrade through it and form a new one.

If I increase the sharpening angle on the 6k, the lateral pressure on the apex is so high (even with a feather touch) that it bends the apex away.
In that case, the burr remains and can actually grow. After a few passes (abrasion), the contact area increases and I see a normal microbevel form once we abrade through the burr.

Keep in mind that these are low angles, so the apex is much more plastic than you would see on a 45 degree bevel, say.

12

[quote quote=“wickededge” post=24482]…

If I increase the sharpening angle on the 6k, the lateral pressure on the apex is so high (even with a feather touch) that it bends the apex away.

In that case, the burr remains and can actually grow. After a few passes (abrasion), the contact area increases and I see a normal micro-bevel form once we abrade through the burr.

Keep in mind that these are low angles, so the apex is much more plastic than you would see on a 45 degree bevel, say.[/quote]

I once watched an episode of “How It’s Made” where they were making straight razors. At the end, the fellow doing the sharpening would press the edge flat against his thumbnail. You could easily see the edge flex, so thin it looked like foil. I think I’ll buy one just to try sharpening it.

How do you put a micro-bevel on something that flexible?

13

interesting to see what you find Josh on the wood. This is the same thing I fight sometimes. Micro wire edge is a good way to describe it. normal burr or larger wire edge I can deal with. The micro wire edge is the hard one for me. Nice way to detect it. easy test..

14

[quote quote=“ToddSimpson” post=24491][quote quote=“razoredgeknives” post=24477]…
If it is only shaving on one side at this point then you know you have a wire edge and it’s not a clean fresh apex - i.e. it won’t be as durable of an edge.[/quote]

Will it shave on the side you strop or the side away from the strop?

[quote quote=“wickededge” post=24482]…

I’d like more information, like number of strokes, pressure etc… I’d also love to see him test edge trailing to start and then finishing with a few, light, edge leading strokes with the 6k stone, particularly at a higher angle, without trying to fold over the burr on wood. Then I’d like to see him lower the angle a little and strop the blade.[/quote]

This was done several times on different blades just to confirm that these observations were repeatable. I did vary pressure and number of strokes over those trials and the results were consistent.

On switching from edge trailing to edge leading - the bulk of a large (edge-trailing) burr is usually broken within one or two strokes on the finer stone, but the apex is not clear until we abrade through it and form a new one.

If I increase the sharpening angle on the 6k, the lateral pressure on the apex is so high (even with a feather touch) that it bends the apex away.
In that case, the burr remains and can actually grow. After a few passes (abrasion), the contact area increases and I see a normal microbevel form once we abrade through the burr.

Keep in mind that these are low angles, so the apex is much more plastic than you would see on a 45 degree bevel, say.[/quote]

After reading the comments below this last article, didn’t know you didn’t have a wicked edge… I, and I’m sure others, would be willing to donate to the cause so to speak to get you one :wink: Thanks for all the research and time you put into your blog, it’s much appreciated.

So it sounds like what you are saying is that you can go edge trailing w/ a micro bevel on a razor, you just have to do a certain number of strokes (say 20-30 vs. just 1-2) to increase the contact area of the apex so a normal microbevel will form?

15

It’s definitely a very flimsy wire edge as one pass on the pant leg will flip it… shoot I could probably strop it on my arm one pass and it would do the same thing. I have no idea if this really affects performance or longevity of edge retention in EDC type situations though, I just suspect it won’t be as durable as a clean apex would be. may not matter tho…

16

[quote quote=“razoredgeknives” post=24495]…

So it sounds like what you are saying is that you can go edge trailing w/ a micro bevel on a razor, you just have to do a certain number of strokes (say 20-30 vs. just 1-2) to increase the contact area of the apex so a normal microbevel will form?[/quote]

Either edge trailing or edge leading, the contact area is extremely small and therefore the pressure is extremely high when you first start to micro-bevel. Once the micro-bevel is established, the contact area increases and the pressure can be low enough to abrade normally rather than simply deforming the apex.

17

[quote quote=“ToddSimpson” post=24498][quote quote=“razoredgeknives” post=24495]…

So it sounds like what you are saying is that you can go edge trailing w/ a micro bevel on a razor, you just have to do a certain number of strokes (say 20-30 vs. just 1-2) to increase the contact area of the apex so a normal microbevel will form?[/quote]

Either edge trailing or edge leading, the contact area is extremely small and therefore the pressure is extremely high when you first start to micro-bevel. Once the micro-bevel is established, the contact area increases and the pressure can be low enough to abrade normally rather than simply deforming the apex.[/quote]

By God, that actually makes sense to me today. It will result in a slightly larger “micro bevel” but it will be right. and when I say slightly it is all in context of how small it already is ya know?

Would all of this still hold true if you were making a micro bevel with a 400 grit stone to give it some teeth? And then a little refining of the micro bevel with some ceramics after?

18

Hey Josh,

I am finally getting my head around this one. After your first post I didn’t quite follow but now I understand you are talking about a very, very, small burr.

Would a strop work?
Would it risk rounding the edge?
If the burr is so small it comes off on jeans then this could contaminate the strop for those of us who care enough to wipe the blade down between changing different strops.

I like the felt block. Looks like dragging/cutting the edge straight into anything would accomplish this. Leather, many sheets of paper, a rag, phone book, soft wood.

I would like to see the difference under high magnification as well as see the burr that is removed.

19

[quote quote=“Geocyclist” post=24501]Hey Josh,

I am finally getting my head around this one. After your first post I didn’t quite follow but now I understand you are talking about a very, very, small burr.

Would a strop work?
Would it risk rounding the edge?
If the burr is so small it comes off on jeans then this could contaminate the strop for those of us who care enough to wipe the blade down between changing different strops.

I like the felt block. Looks like dragging/cutting the edge straight into anything would accomplish this. Leather, many sheets of paper, a rag, phone book, soft wood.

I would like to see the difference under high magnification as well as see the burr that is removed.[/quote]

Yep! Yeah I’m not saying that the burr comes off on my jeans I’m saying that it just flips it. It could probably be better described as a wire edge than a burr.

As clay referenced , This is what an edge looks like when you cut into wood to try to remove the burr - not so good! It just folds the wire edge 180 degrees.

20

[quote quote=“razoredgeknives” post=24502][quote quote=“Geocyclist” post=24501]Hey Josh,

I am finally getting my head around this one. After your first post I didn’t quite follow but now I understand you are talking about a very, very, small burr.

Would a strop work?
Would it risk rounding the edge?
If the burr is so small it comes off on jeans then this could contaminate the strop for those of us who care enough to wipe the blade down between changing different strops.

I like the felt block. Looks like dragging/cutting the edge straight into anything would accomplish this. Leather, many sheets of paper, a rag, phone book, soft wood.

I would like to see the difference under high magnification as well as see the burr that is removed.[/quote]

Yep! Yeah I’m not saying that the burr comes off on my jeans I’m saying that it just flips it. It could probably be better described as a wire edge than a burr.

As clay referenced , This is what an edge looks like when you cut into wood to try to remove the burr - not so good! It just folds the wire edge 180 degrees.

[/quote]

That burr looks like it’s so fine it could be easily flipped back to the other side and would break off pretty quickly. I’m guessing that flipping it back and forth would make the metal brittle they way that Cliff Stamp describes. Judging by the scale in the image, it looks as though the burr is several microns tall and just a fraction of a micron thick. I’d love to see what’s underneath were the burr to be popped off.