Burr removal

[hibbs00]

Ended up working on a friend's knife instead of mine. Got his thinned out pretty good and after a burr on each side, burr minimization I did light cross grit passes and lastly extremely light raised angle passes. Sharpest blade I've gotten so far. Kinda wish I did it on mine haha but mine is next

 

[Benuser]

I've wondered exactly this myself, and tbh I don't know enough about the science and metallurgy of what's going on to be able to answer it satisfactorily. Because you're right; bevel geometry shouldn't make a difference, paper towel falls away as you cut it, it's not a carrot, you can't wedge in paper towel. Given two otherwise identical knives, one thicker one thinner, but sharpened at the same angle in the same way - they should also cut paper in the same way (afaics).

But all of my lived experience says that bevel geometry does make a difference. That Sab didn't do that before my latest round of thinning, even when finished on a Coti or Washita, let alone a King 800. And I see it at work too when sharpening other people's knives that are fat bte. At the extremes it can actually be quite difficult to get any kind of working edge onto some really thick knives.

My only possible guess as to what's happening is that if the steel is thicker leading into the edge; then perhaps burrs and edges actually form in a different way compared to a knife that is properly thin leading into the edge(?). That's pure conjecture, but it's the only reason I can think of to explain it.

Just a guess: with the thicker knife, geometry, especially asymmetry comes in, more than with a thin one. If you're used to knives with a strong asymmetry you may very well cut straight. If you do expect a symmetric geometry though, an asymmetric yo-deba may be problematic. I see young fellows using a very tight grip having problems with steering. Their tight grip causes a lot of unnecessary friction.

 

[hibbs00]

How does everyone feel about 3 step plateau sharpening? Has anyone tried it? Is it really as easy as Cliff Stamp says it is?

 

[Benuser]

How does everyone feel about 3 step plateau sharpening? Has anyone tried it? Is it really as easy as Cliff Stamp says it is?

It is an interesting concept to avoid burr formation and wasting material on hard steels. The idea is stopping in time with coarse stones, removing the old apex and forming a new one with the finest stone only. Might be interesting when working on hard, simple carbon like Shirogami. I should add that conventional deburring works very well with those same steels.
Not your case, as your best knife is a Wüsthof: far from hard, likely to form a burr long before the very edge got reached, no fine grit involved as that steel won't hold a polished edge. Another shortcut you're looking for but is far from relevant with the involved steel. It seems to me your problem is still in feeling a burr and getting rid of it with the available 1k stone, which should be your final one with those soft stainless. Complicating things with a finer grit and a microbevel won't help you. Soft stainless is horrible to learn sharpening on.

 

[mengwong]

During last night's session I tried to pay attention to one key element: when deburring at a higher angle, how much pressure is correct, and what angle is ideal, to knock off the old burr without either

1. grinding a new high-angle bevel – due to too much pressure – which necessitates re-thinning to correct

2. folding over the burr – due to too little pressure – which necessitates low-angle edge-trailing to unfurl

hitting the sweet spot between these extremes allows one to be efficient in deburring which in turn minimizes rounding and other mis-beveling error.

 

[Benuser]

During last night's session I tried to pay attention to one key element: when deburring at a higher angle, how much pressure is correct, and what angle is ideal, to knock off the old burr without either

1. grinding a new high-angle bevel – due to too much pressure – which necessitates re-thinning to correct

2. folding over the burr – due to too little pressure – which necessitates low-angle edge-trailing to unfurl

hitting the sweet spot between these extremes allows one to be efficient in deburring which in turn minimizes rounding and other mis-beveling error.

I would say, flipping the burr without it getting any smaller by abrading is due to too high a pressure.

 

[hibbs00]

It is an interesting concept to avoid burr formation and wasting material on hard steels. The idea is stopping in time with coarse stones, removing the old apex and forming a new one with the finest stone only. Might be interesting when working on hard, simple carbon like Shirogami. I should add that conventional deburring works very well with those same steels.
Not your case, as your best knife is a Wüsthof: far from hard, likely to form a burr long before the very edge got reached, no fine grit involved as that steel won't hold a polished edge. Another shortcut you're looking for but is far from relevant with the involved steel. It seems to me your problem is still in feeling a burr and getting rid of it with the available 1k stone, which should be your final one with those soft stainless. Complicating things with a finer grit and a microbevel won't help you. Soft stainless is horrible to learn sharpening on.

It's true just staying on the 1k I don't get the edge I'm looking for without at least 2 or 3 light passes on the 6k, my edges have been great lately. Not what I want yet but I understand that will take a lot of practice and most people don't get that kind of edge unless you're Oli @cotedupy
I've never looked for a shortcut, I understand there are no shortcuts to sharpening. I'm looking for the best methods. I believe there is always a right and wrong way and always better ways and worse ways and believe everything has a "best" way to do it and that's just what I'm after

 

[Desert Rat]

How does everyone feel about 3 step plateau sharpening? Has anyone tried it? Is it really as easy as Cliff Stamp says it is?

If he was taking alternating edge leading passes after bread knifing the edge he may not have been raising a burr or atleast one that he can feel.

This alternating edge leading sharpening was mentioned in the last Science of Sharp article on burrs.

We can go back and look at the literature from Pike and others that promoted alternating edge leading strokes with oil stones and we will find no mention of burr removal. Still today we can visit Dan's whetstone and see his instruction on how to use Arkansas stones and it will be alternating edge leading and no mention of burrs.

I have never seen an edge of a stone that didn't get sharper from a strop so there is probably some burr there but I think an augment might be made for it being inconsequential.

 

[hibbs00]

If he was taking alternating edge leading passes after bread knifing the edge he may not have been raising a burr or atleast one that he can feel.

This alternating edge leading sharpening was mentioned in the last Science of Sharp article on burrs.

We can go back and look at the literature from Pike and others that promoted alternating edge leading strokes with oil stones and we will find no mention of burr removal. Still today we can visit Dan's whetstone and see his instruction on how to use Arkansas stones and it will be alternating edge leading and no mention of burrs.

I have never seen an edge of a stone that didn't get sharper from a strop so there is probably some burr there but I think an augment might be made for it being inconsequential.

I did find it interesting Cliff claims a burr does nothing for his edge.
https://knifeplanet.net/2015/10/21/interview-cliff-stamp/

I haven't tried it yet, I still need to get better at burr based sharpening first, but I like that he says with the plateau method, once it stops reflecting light you can skip grit do you can go from a 300 grit to form the edge and then go to 6k to form the apex bevel or the micro bevel. Again, I know his method would be a while other level and would require a ton of practice but I find it very interesting

 

[Desert Rat]

I did find it interesting Cliff claims a burr does nothing for his edge.
https://knifeplanet.net/2015/10/21/interview-cliff-stamp/

I haven't tried it yet, I still need to get better at burr based sharpening first, but I like that he says with the plateau method, once it stops reflecting light you can skip grit do you can go from a 300 grit to form the edge and then go to 6k to form the apex bevel or the micro bevel. Again, I know his method would be a while other level and would require a ton of practice but I find it very interesting

He put a secondary bevel on that knife or I guess you could call it a large micro bevel.

I actually sharpen a lot like he demonstrated on most knives, especially hard use outdoor knives. Take the knife to almost sharp at a more acute angle on a coarse grit stone and then go to my intended angle usually at a grit change, nothing radical a few degrees or so. It approximates a convex edge, makes touch ups quick and easy for awhile, then when it becomes to thick again rinse repeat.

 

[hibbs00]

He put a secondary bevel on that knife or I guess you could call it a large micro bevel.

I actually sharpen a lot like he demonstrated on most knives, especially hard use outdoor knives. Take the knife to almost sharp at a more acute angle on a coarse grit stone and then go to my intended angle usually at a grit change, nothing radical a few degrees or so. It approximates a convex edge, makes touch ups quick and easy for awhile, then when it becomes to thick again rinse repeat.

I'm getting better and better at burr based sharpening. I'm going to have to try that method soon. In the summer months I do a lot of bushcraft/camping type of stuff. What kind of grit and angle do you recommend for outdoor knives?

 

[Benuser]

He put a secondary bevel on that knife or I guess you could call it a large micro bevel.

I actually sharpen a lot like he demonstrated on most knives, especially hard use outdoor knives. Take the knife to almost sharp at a more acute angle on a coarse grit stone and then go to my intended angle usually at a grit change, nothing radical a few degrees or so. It approximates a convex edge, makes touch ups quick and easy for awhile, then when it becomes to thick again rinse repeat.

That would mean that the apex only got touched by a fine stone. No good idea with the OP's soft stainless with their large carbides who aren't abraded with fine grits. Those steels already miss edge stability, and such an edge simply won't hold. Could be interesting though with carbons and finely grained stainless.
The idea of somewhat convexing the bevels may be helpful even with soft stainless, if taking place with the first stone. Apart from the extra stability it offers, deburring a convex edge is easier than a pure V-form, as only a very small part of the bevel got touched by the stone, which offers far more feedback.
Please remember the soft stainless edges won't hold where high grits got used. The limit I've seen with Krupp's 4116 is around the 1.2 or 1.4k according to the Japanese standard JIS. The OP's Shapton is a 1k, whose grit corresponds to 700 or 800 JIS. There is some room for refinement. I would like to know how other members experienced the Shapton Pro 2k with 4116. The stone delivers some 1.4k edge, and is very pleasant with deburring.

 

[Mr.Wizard]

That would mean that the apex only got touched by a fine stone. No good idea with the OP's soft stainless with their large carbides who aren't abraded with fine grits.

Why would not the carbides in "soft stainless" be abraded by fine grit? If you mean vanadium carbide we have a very different working definition of "soft stainless."

 

[Benuser]

Why would not the carbides in "soft stainless" be abraded by fine grit? If you mean vanadium carbide we have a very different working definition of "soft stainless."

Vanadium carbides in Wüsthof? Had the chromium carbides in mind, which an 6k as the OP uses will leave untouched while removing some of the surrounding, the notorious weak matrix. The carbides break out, the edge crumbles.

 

[harken]

I did find it interesting Cliff claims a burr does nothing for his edge.
https://knifeplanet.net/2015/10/21/interview-cliff-stamp/

I haven't tried it yet, I still need to get better at burr based sharpening first, but I like that he says with the plateau method, once it stops reflecting light you can skip grit do you can go from a 300 grit to form the edge and then go to 6k to form the apex bevel or the micro bevel. Again, I know his method would be a while other level and would require a ton of practice but I find it very interesting

I’ll leave this here for the last bit : https://scienceofsharp.com/2015/07/09/its-too-big-of-a-jump/

Big jumps on grit aren’t a bad thing (but it’s a waste for soft stainless, as stated previously, beyond 1k or so).

 

[hibbs00]

Finally got an edge to push cut just off of the 1k stone. No strop and no 6k stone. Thinned the blade until I could barely see the apex edge on both sides using the SP220 (Not the best thinning job, some spots are higher up the blade than others) polished the thinning scratch pattern on the 1k and then formed a burr on both sides at about 15 degrees, then less pressure forming a smaller burr on both sides and crossed grit pattern as a burr reduction method followed by slightly higher angle, alternating passes, very very low pressure and finally light alternating passes back at the 15 degree sharpening angle. Can almost push cut at the 90/90/90 degree but needs a small tilt to push cut. I'm pretty proud of this edge

 

[Mr.Wizard]

Vanadium carbides in Wüsthof? Had the chromium carbides in mind, which an 6k as the OP uses will leave untouched while removing some of the surrounding, the notorious weak matrix. The carbides break out, the edge crumbles.

I've seen the scienceofsharp articles documenting raised vanadium carbides but I haven't seen evidence of this with chromium carbides on alumina or silicon carbide stones. D2 grinds quickly enough on these, and it has very large chromium carbides; how do you explain this if alumina cannot adequately cut chromium carbide?

 

[Benuser]

Finally got an edge to push cut just off of the 1k stone. No strop and no 6k stone. Thinned the blade until I could barely see the apex edge on both sides using the SP220 (Not the best thinning job, some spots are higher up the blade than others) polished the thinning scratch pattern on the 1k and then formed a burr on both sides at about 15 degrees, then less pressure forming a smaller burr on both sides and crossed grit pattern as a burr reduction method followed by slightly higher angle, alternating passes, very very low pressure and finally light alternating passes back at the 15 degree sharpening angle. Can almost push cut at the 90/90/90 degree but needs a small tilt to push cut. I'm pretty proud of this edge

That's good news! What I don't understand, is why you go back to your sharpening angle after having slightly increased it for deburring. For performance it won't matter much whether the edge ends at 18 or 15° per side. But there's a serious risk of creating a new burr.

 

[Desert Rat]

I'm getting better and better at burr based sharpening. I'm going to have to try that method soon. In the summer months I do a lot of bushcraft/camping type of stuff. What kind of grit and angle do you recommend for outdoor knives?

I like toothy edges on my outdoor knives. very toothy compared to most of my kitchen knives. A 1k stone would be fine. For carveing tasks a really refined edge is fine though.

Toothy edges just out perform a refined edge for rough tasks. Joe here has cut a lot of rope proving it.

 

[Benuser]

I've seen the scienceofsharp articles documenting raised vanadium carbides but I haven't seen evidence of this with chromium carbides on alumina or silicon carbide stones. D2 grinds quickly enough on these, and it has very large chromium carbides; how do you explain this if alumina cannot adequately cut chromium carbide?

I suppose you're familiar Roman Landes notion of edge instability, which applies very clearly to Krupp's 4116, used by Wüsthof, Zwilling/Henckels, Burgvogel/Messermeister. The cause is in the large carbides in a weak matrix. Large carbides allone in other steel types like 440C or 19C27 don't show the same problem, at least not to the same degree.
The reason to start the progression with relatively coarse stones is indeed in abrading chromium carbides, as in the case of your example with D2. Give it a try: sharpen 4116 with Belgian Blue, or with a 6 or 8k only, with no coarser stone before. With simple carbons it will work. With 4116 the edge will crumble.

 

[hibbs00]

That's good news! What I don't understand, is why you go back to your sharpening angle after having slightly increased it for deburring. For performance it won't matter much whether the edge ends at 18 or 15° per side. But there's a serious risk of creating a new burr.

I don't understand why but if I leave it after the higher angle it's sharp but after 4 or 5 15 degree angle passes on each side it seems to boost the sharpness

 

[hibbs00]

I like toothy edges on my outdoor knives. very toothy compared to most of my kitchen knives. A 1k stone would be fine. For carveing tasks a really refined edge is fine though.

Toothy edges just out perform a refined edge for rough tasks. Joe here has cut a lot of rope proving it.

Idk if this is true, it's just what I am picturing but would a toothy edge dull faster because the small teeth will break or roll over? I know I'm probably wrong, like I said it's just what I'm picturing in my head

 

[Mr.Wizard]

Testing (not mine) shows that a toothy edge lasts longer than a polished edge in slicing, however it does not last as long as a polished edge in pure push cutting, like whittling, so it depends on how the edge is loaded in use.

 

[hibbs00]

Testing (not mine) shows that a toothy edge lasts longer than a polished edge in slicing, however it does not last as long as a polished edge in pure push cutting, like whittling, so it depends on how the edge is loaded in use.

Hmmm. Interesting. I don't really slice much, my knife is mostly used for splitting and feathering wood. I've never tried this, only heard about it but what about one of those where one side is fine grit and the other side is coarse? Would that kind of be like best of both worlds?

 

[Mr.Wizard]

Hmmm. Interesting. I don't really slice much, my knife is mostly used for splitting and feathering wood. I've never tried this, only heard about it but what about one of those where one side is fine grit and the other side is coarse? Would that kind of be like best of both worlds?

Applied in a particular way that can make a slicing edge that lasts a long time but I don't believe it would work too well for push cutting with force as the finger-like burr that extends edge life in abrasive edge wear would not be as strong as a fully supported apex. See: https://scienceofsharp.com/2021/06/15/dual-grit-sharpening/

 

[Mr.Wizard]

I suppose you're familiar Roman Landes notion of edge instability, which applies very clearly to Krupp's 4116, used by Wüsthof, Zwilling/Henckels, Burgvogel/Messermeister. The cause is in the large carbides in a weak matrix. Large carbides allone in other steel types like 440C or 19C27 don't show the same problem, at least not to the same degree.
The reason to start the progression with relatively coarse stones is indeed in abrading chromium carbides, as in the case of your example with D2. Give it a try: sharpen 4116 with Belgian Blue, or with a 6 or 8k only, with no coarser stone before. With simple carbons it will work. With 4116 the edge will crumble.

I re-read both parts of https://knifesteelnerds.com/2018/08/27/what-is-edge-stability/ and I see nothing about low grit versus high grit, only low and high edge angle, an obtuse angle being needed for less stable steels. I don't see how coarse stones do anything to improve stability when used before a fine stone of the same abrasive type.

 

[Benuser]

I don't understand why but if I leave it after the higher angle it's sharp but after 4 or 5 15 degree angle passes on each side it seems to boost the sharpness

I would be interested to know if that boosted sharpness does last after some board work. I wouldn't be surprised if it is a wire edge you're creating, a thin burr on top of the edge that's crazy sharp but fails after board contact, leaving a severely damaged edge behind.

 

[hibbs00]

I would be interested to know if that boosted sharpness does last after some board work. I wouldn't be surprised if it is a wire edge you're creating, a thin burr on top of the edge that's crazy sharp but fails after board contact, leaving a severely damaged edge behind.

When I'm done sharpening I do do a couple board slices like @mengwong recommended. It still seemed fine after. Is it possible to form a wire edge with extremely low pressure? Pretty much just the weight of the knife with leading passes?
Do leading passes completely stop burr formation or does it just help reduce the chance?

 

[Benuser]

When there is abrasion, some burr formation will occur. Even in this case, with light alternating edge leading strokes. Much less than edge trailing strokes, but still.
Use in the kitchen can tell you whether it's a wire edge. Crazy sharp, and suddenly very dull.

 

[hibbs00]

When there is abrasion, some burr formation will occur. Even in this case, with light alternating edge leading strokes. Much less than edge trailing strokes, but still.
Use in the kitchen can tell you whether it's a wire edge. Crazy sharp, and suddenly very dull.

I'll watch out for it. Is it possible the light leading passes back at the original angle just refined the edge a little more or is it probably a wire edge?