The burr nobody talks about

[notcrazy]

New member, first post. This has been my go to site for knife info for years and finally decided I should join.
I have been sharpening with the Lansky guided system for over 30 years cuz I can't sharpen freehand, I just can't. I have knives to prove it.

OK on to the topic. I get a burr at the top of my secondary bevel where it meets the primary grind. Am I the only person in the world this happens to? I have searched the internet countless times looking for this issue and found nothing. It is easy to remove this burr but I can't believe nobody has mentioned it, ever, anywhere. So much good info out there for newbie and experienced sharpeners. So much discussion of edge burrs but nothing about a burr at the top of the secondary bevel.
This burr frequently (for me) manifests itself as a sort of bump or step or ledge but can also be a true wire type burr. I think it depends on blade steel, sharpening pressure, the difference between the primary and secondary angles, phases of the moon, who knows.
Freehand sharpening may not produce this burr due to the slightly inconsistent sharpening angle inherent with that method but if you use a guided system and are sharpening the entire face of the secondary bevel then this must be happening to someone besides me unless the laws of physics are different in my world.
This burr is real and can affect the cutting ability of the knife. Think mirror polished edge and then put a little wall at the top of your edge bevel. Not so good for slicing. Not trying to be controversial or start any arguments, just wondering why nobody mentions this.

 

[kreisler]

sharpening the entire face of the secondary bevel then this must be happening to someone besides me unless the laws of physics are different in my world.

i doht even know anymore what the "secondary bevel" is. or if i read about it, i will have forgotten about it the next day.
got some photos to share?
if the steel is premium, you woht get burrs all over the place. with premium i mean hard steels.
with a soft steel or with a ductile steel, then yes.

 

[old4570]

I hear you ,,, '

You mean , the bevel / edge ..
You get a bur between the edge / bevel and then the rest of the blade ..

Sorry for the rubbish picture ..
Yeah , if you use a guided system .. Depending on your movements ( stone . diamond ) You can move material in both directions ..
Now a lot of people say , you should sharpen from the edge & back ( arrows in the picture or towards the blade ) .. This then can also move material up the blade creating a lump or rough spot ..
Might be why some sharpen - away from the blade ?
But yes .. Have noticed this .. And sometimes go to the trouble of stropping it away .

 

[foxhunter2]

photos will help

 

[notcrazy]

Old4570 has it exactly right. His illustration is perfect. Thank you! I couldn't bring myself to sharpen away from the edge instead of into it. Besides being the wrong way in my book it seems that would just increase the size of the edge burr and I try to not get a big edge burr. I don't know how you strop that burr off. Think that would take forever. I usually use a medium stone and just a few strokes to get rid of it.
I can get this burr on all steels- 440c, vg-10, s35, cpm-20cv, d2, 8cr...., Etc.
Can't do photos. I'd never get one to actually show the burr.

 

[Crag the Brewer]

First off.... Welcome.
I was a Long time lurker, too.

What kind of angles are you sharpening at. I'm thinking that the shallower, the less burr, or No?

* I free hand sharpen, but I understand what you are saying.

 

[SwissHeritageCo]

Weird. Never heard of a flats to bevel bur before.. but I don't use guided systems.

 

[Blade Lab]

I can't say I've ever noticed a shoulder burr.

 

[Obsessed with Edges]

I'd seen that burr at the crisp shoulder of the secondary bevel once, on a factory edge from Case in their 'Tru-Sharp' 420HC (HRC 55-57). They grind their edges on belts moving into the edge, which at that particular time left a BIG burr at the shoulder of the edge grind. I felt the burr by running my thumbnail down toward the edge from the spine of the blade - the big burr at the shoulder of the edge grind stopped my nail's motion cold, like running into a curb. I'd only noticed that phenomenon on the one blade and hadn't otherwise seen it since, on factory edges or on my own edges.

And guided systems in particular can produce some very wide and very thin burrs for the reason mentioned: the angle never changes, so the steel keeps getting drawn out and thinned to ridiculous extremes at the edge (and apparently at the shoulder of the edge bevel, as you noted). With the little bit of angle variation coming with freehand sharpening, those burrs will almost always break away or get torn away before they get so wide.

Most burrs in general will be reduced or minimized by greatly reducing the applied pressure during grinding or honing. If pressure is heavy at all, the burrs will tend to be much thicker, tougher and more stubborn to clean up. To some degree, I'm sure they'll still form under these circumstances. But they'll be minimal enough as to be insignificant or unnoticeable in use.

 

[SwissHeritageCo]

First off.... Welcome.
I was a Long time lurker, too.

What kind of angles are you sharpening at. I'm thinking that the shallower, the less burr, or No?

* I free hand sharpen, but I understand what you are saying.

I'd seen that burr at the crisp shoulder of the secondary bevel once, on a factory edge from Case in their 'Tru-Sharp' 420HC (HRC 55-57). They grind their edges on belts moving into the edge, which at that particular time left a BIG burr at the shoulder of the edge grind. I felt the burr by running my thumbnail down toward the edge from the spine of the blade - the big burr at the shoulder of the edge grind stopped my nail's motion cold, like running into a curb. I'd only noticed that phenomenon on the one blade and hadn't otherwise seen it since, on factory edges or on my own edges.

And guided systems in particular can produce some very wide and very thin burrs for the reason mentioned: the angle never changes, so the steel keeps getting drawn out and thinned to ridiculous extremes at the edge (and apparently at the shoulder of the edge bevel, as you noted). With the little bit of angle variation coming with freehand sharpening, those burrs will almost always break away or get torn away before they get so wide.

Most burrs in general will be reduced or minimized by greatly reducing the applied pressure during grinding or honing. If pressure is heavy at all, the burrs will tend to be much thicker, tougher and more stubborn to clean up. To some degree, I'm sure they'll still form under these circumstances. But they'll be minimal enough as to be insignificant or unnoticeable in use.

You really do live up to the moniker

 

[notcrazy]

First off.... Welcome.
I was a Long time lurker, too.

What kind of angles are you sharpening at. I'm thinking that the shallower, the less burr, or No?

* I free hand sharpen, but I understand what you are saying.

Generally around 20 to 15 deg per side but it depends on the knife. Those are guesstimated angles since the Lansky settings are not real world numbers. I agree that the shallower angles probably result in smaller burrs.
Thanks for the welcome and I have to say you freehand sharpeners my heros!

 

[notcrazy]

I can't say I've ever noticed a shoulder burr.

I so wanted to call it a shoulder burr in my original post but didn't know if anyone would get that. I was wrong.

 

[notcrazy]

I'd seen that burr at the crisp shoulder of the secondary bevel once, on a factory edge from Case in their 'Tru-Sharp' 420HC (HRC 55-57). They grind their edges on belts moving into the edge, which at that particular time left a BIG burr at the shoulder of the edge grind. I felt the burr by running my thumbnail down toward the edge from the spine of the blade - the big burr at the shoulder of the edge grind stopped my nail's motion cold, like running into a curb. I'd only noticed that phenomenon on the one blade and hadn't otherwise seen it since, on factory edges or on my own edges.

And guided systems in particular can produce some very wide and very thin burrs for the reason mentioned: the angle never changes, so the steel keeps getting drawn out and thinned to ridiculous extremes at the edge (and apparently at the shoulder of the edge bevel, as you noted). With the little bit of angle variation coming with freehand sharpening, those burrs will almost always break away or get torn away before they get so wide.

Most burrs in general will be reduced or minimized by greatly reducing the applied pressure during grinding or honing. If pressure is heavy at all, the burrs will tend to be much thicker, tougher and more stubborn to clean up. To some degree, I'm sure they'll still form under these circumstances. But they'll be minimal enough as to be insignificant or unnoticeable in use.

YES. You get it. I am notcrazy.
I have recently started using diamond instead of stones and they cut so well I have Really lightened up my pressure and can reduce the number of strokes too so hopefully I will see the shoulder burrs reduced. We'll see.

 

[Obsessed with Edges]

YES. You get it. I am notcrazy.
I have recently started using diamond instead of stones and they cut so well I have Really lightened up my pressure and can reduce the number of strokes too so hopefully I will see the shoulder burrs reduced. We'll see.

That was the 2nd thought I had... Some stones that struggle a little bit to cut the steel will aggravate burring issues as well. It's sort of a pet peeve of mine with cheap aluminum oxide stones in particular. If the grit is just poor quality (not sharp, etc.), or if it's prone to clogging easily or wears (glazes) too quickly, it'll just make burring issues worse because it can't cut the steel cleanly at a light touch. So, when the steel eventually gets thin enough near the edge, instead of being cleanly abraded away, it'll tend to just deflect away from the stone and the burr will never clean up past a certain point. That's why I favor good quality diamond hones, even for simpler steels. They'll still cut & grind easily at the lightest touch, and that makes a difference with burrs especially. Some good-quality diamond hones need next to nothing, in terms of deburring work after the finishing passes are done.

 

[notcrazy]

That was the 2nd thought I had... Some stones that struggle a little bit to cut the steel will aggravate burring issues as well. It's sort of a pet peeve of mine with cheap aluminum oxide stones in particular. If the grit is just poor quality (not sharp, etc.), or if it's prone to clogging easily or wears (glazes) too quickly, it'll just make burring issues worse because it can't cut the steel cleanly at a light touch. So, when the steel eventually gets thin enough near the edge, instead of being cleanly abraded away, it'll tend to just deflect away from the stone and the burr will never clean up past a certain point. That's why I favor good quality diamond hones, even for simpler steels. They'll still cut & grind easily at the lightest touch, and that makes a difference with burrs especially. Some good-quality diamond hones need next to nothing, in terms of deburring work after the finishing passes are done.

I switched to diamond hones at the same time I moved my sharpening to a different room. Now I have better lighting and I can see edge burrs better and am sort of obsessing on them again. I made diamond hones from old Lansky holders and sections cut from DMT diamond plates. Man those things cut! I believe you may be right about good quality diamonds needing very little deburring work. The Lansky diamonds are meh. Just used the coarse for hogging off material but the DMT medium is even faster doing that. The DMT x-fine gives a great finish and I kinda just float it over the edge. Takes out the previous hones scratches real quick and if I am careful or lucky it seems to cut the burr right off. Still learning after 30 years. Where were diamonds when I started this hobby?

 

[old4570]

Yes , many variables that can contribute to the "SHOULDER BUR" ( Blade Lab ) , such as pressure , angle , sharpening motion , and condition of the stone ..
I noticed that with a nice crisp cutting 600 grit diamond the shoulder bur is minimized or negated ..
My well worn and dulling 180 grit diamond is a cause of shoulder bur , but it still produces a edge .
So now I clean with the fresh 600 grit diamond ..

( Yeah , I should probably break out a fresh 180 grit cutter / sharpener - or not )

 

[notcrazy]

Yes , many variables that can contribute to the "SHOULDER BUR" ( Blade Lab ) , such as pressure , angle , sharpening motion , and condition of the stone ..
I noticed that with a nice crisp cutting 600 grit diamond the shoulder bur is minimized or negated ..
My well worn and dulling 180 grit diamond is a cause of shoulder bur , but it still produces a edge .
So now I clean with the fresh 600 grit diamond ..

( Yeah , I should probably break out a fresh 180 grit cutter / sharpener - or not )

Yep. And all those variables affect the edge burr too.
Thanks for using the term "shoulder bur". Maybe it will really catch on and show up in a sharpening tutorial someday. Then we can start discussing the tip burr.