Impossible to raise a burr?

R

roygbiv092834

Joined
Jun 23, 2026
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Hello everyone, I'm asking here because I cant find helpful resources anywhere else.
I'm using p600 sandpaper adhered to a flat granite slab and sharpening a flexcut kn12 (a wood carving knife with a 2 straight bevels). When doing edge trailing strokes, no matter how many I do, I can never feel any burr when trying to nick it from the opposite side perpendicularly. Also sharpie gets removed along the entire face when used. However, I've noticed that if i push the edge to one side, i can 'fold it over' letting me feel a nick like normal. Obviously this isnt very helpful as this in plane burr (?) is weak and i cant seem to sharpen it without making one

Strangely enough I can get a burr perfectly fine with an opinel so I suspect its the grind, steel, or user error

Any advice?

Thanks
 
Hello my colorful friend, and welcome to Bladeforums. Edge leading is more reliable for burr formation in my experience. With edge trailing, if your pressure is too light or your contact isn’t centered on the apex, you can end up polishing the bevel rather than removing enough steel to raise a burr.
 
I'm sure you've considered this... some steels are more prone to create a burr than others. In Vadim Karichuck of Australian Knife Grinders, states that you can generate positive or negitive burrs as you grind. A positive burr is what you're looking for and probably use to seeing. Negitive burrs chip or break of during the grinding process. Hard steels are most susceptible to this.
In the back of Vadim's book, "Knife Deburring" there is a table showing his sharpening processes for many different types of steel. With those steels that don't develop a good positive burr (negitive) the stropping process is different focusing on gentle exact angle progressive stropping as opposed to an elevated angle to cut the burr off.
He discusses positive and negative burrs at length and how to deal with each.

An excellent read, I highly recommend it!
"Knife Deburring" by Vadim Karichuck.
 
David Mary said:
Hello my colorful friend, and welcome to Bladeforums. Edge leading is more reliable for burr formation in my experience. With edge trailing, if your pressure is too light or your contact isn’t centered on the apex, you can end up polishing the bevel rather than removing enough steel to raise a burr.
Click to expand...
Thanks for the reply, but wont edge leading tear the sandpaper?
 
Gottagofishn said:
I'm sure you've considered this... some steels are more prone to create a burr than others. In Vadim Karichuck of Australian Knife Grinders, states that you can generate positive or negitive burrs as you grind. A positive burr is what you're looking for and probably use to seeing. Negitive burrs chip or break of during the grinding process. Hard steels are most susceptible to this.
In the back of Vadim's book, "Knife Deburring" there is a table showing his sharpening processes for many different types of steel. With those steels that don't develop a good positive burr (negitive) the stropping process is different focusing on gentle exact angle progressive stropping as opposed to an elevated angle to cut the burr off.
He discusses positive and negative burrs at length and how to deal with each.

An excellent read, I highly recommend it!
"Knife Deburring" by Vadim Karichuck.
Click to expand...
I never knew about that, interesting. the knife is carbon steel so i suppose it could be relevant
 
I'd strongly suggest using a good magnifier under BRIGHT light to inspect the edge as you work. If a burr is never forming, it may be due to rounding of the apex before a burr can form. If so, that might point to technique issues like too much variation in held angle. And unless the steel is extra hard, like 60+ HRC, simple carbon steel should form a detectable burr pretty easily. Steels that are super hard, like ZDP-189 at mid-60s HRC, are known for not producing a detectable burr, because it's brittle and will break away just as soon as it begins to form.

You mentioned you can fold over the edge and then detect a burr. If that's the case, the burr IS forming into what's called a 'wire edge' or 'foil edge' which stays essentially aligned straight until some lateral pressure is exerted into it, which then folds it over. That wire edge is something that might be more easily seen under high magnification, brightly lit. I attached a couple of images below of a foil edge I formed on a Victorinox paring knife's edge, using a ceramic hone (Spyderco medium). The foil edge is EXTREMELY thin and folds or moves like very thin foil would do under any sort of pressure. That's the sort of extremely delicate burr that may not be felt with a fingertip and is more likely to be detected visually under bright light with good magnification. The partially separated foil edge pictured below is one that I noticed first under bright light - I initially assumed it to be just a snagged fiber from a microfiber towel I'd used to wipe down the blade as I was working.

And if a foil edge is forming, then removing it is better done with edge-leading passes on a stone. It could also be done edge-leading on the sandpaper, so long as technique is good and the touch is very light. The foil will first deflect upward away from the abrasive surface, after which the blade is flipped over so the leaning burr can be folded back underneath the bevel contacting the abrasive and scrubbed away with very, very light edge-leading passes.
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I sharpen flex cut knives edge trailing with wet dry paper , starting with 320 , then 600 1000 2000
It can take a while to get your first burr and then make sure you polish out the last grit well between the different grits
otherwise you will have knicks in the edge after the strop .
 
Maximumbob54 said:
Cannot stress this little bit enough.
Click to expand...
Wondering…Is this absolute? I feel I can see this problem with good glasses and proper lighting. I may not see the finest detail, but do see the problem and know when it’s no longer a problem —based on sight and cutting performance.

I also realize that as soon as I use the knife, the perfect edge is degraded. So I go for can’t see it and it works as intended with minimum force.
 
Stop mucking about and get what you need to properly sharpen your carving tools.

You can do it with a sandpaper progression, but I would recommend Norton India hard soft combination paired with a hard soft Arkansas combination and a leather strop of some sort, old belt, boots and scrap wood, whatever.
Those examples are really inexpensive buy once and done options (two stones) and if you are a bargain hunter like me, they are readily available in the used market also.

Life is too short not to use really sharp tools.
 
Is there a particular magnifier brand with a bright light that is recommended?
 
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annr said:
Wondering…Is this absolute? I feel I can see this problem with good glasses and proper lighting. I may not see the finest detail, but do see the problem and know when it’s no longer a problem —based on sight and cutting performance.

I also realize that as soon as I use the knife, the perfect edge is degraded. So I go for can’t see it and it works as intended with minimum force.
Click to expand...
For me it was one of those things I didn't know I needed until I didn't know I needed it. If that makes sense. I thought my bifocals were getting the job done and the overhead light was plenty good enough. Now I have a clamp on goose neck lamp I can move around as needed with a nearly overly bright light and bought a cheap but decent magnifier that I occasionally check the edge with to make sure I'm getting all the way to the edge and getting that fine burr. Some of the steels and some of the stones just don't leave those foil edge burrs like cheaper steels do. I was very recently using a resin bonded stone on S30V thinking I must still not be on the very edge yet because there was zero burr but that's just the way that was happening. And I wouldn't have been sure without those extra tools.
 
conan11 said:
Is there a particular magnifier brand with a bright light that is recommended?
Click to expand...
Basically, I'd just recommend something with at least 3X-10X magnification and good lighting. There are lots of possibilities found on Amazon for that. Look for positive reviews and comments about lens clarity and bright lighting in particular.

The photos I posted earlier were taken with a relatively inexpensive USB microscope with much higher magnification, which I bought many years ago. Lots of possibilities for those on Amazon as well. At extremely high magnification, they can sometimes be very tedious to work with though, as the depth of focus at high mag is extremely shallow and sometimes the built-in lighting for them can be difficult to get just right for a clear look without getting some extreme glare off the edge bevels. Can really learn a lot in using them, as I did in discovering that foil edge that I'd previously never seen up close. But patience is a virtue in working with them.
 
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garry3 said:
Stop mucking about and get what you need to properly sharpen your carving tools.

You can do it with a sandpaper progression, but I would recommend Norton India hard soft combination paired with a hard soft Arkansas combination and a leather strop of some sort, old belt, boots and scrap wood, whatever.
Those examples are really inexpensive buy once and done options (two stones) and if you are a bargain hunter like me, they are readily available in the used market also.

Life is too short not to use really sharp tools.
Click to expand...
:thumbsup:

For woodcarving tools, I immediately thought of Norton's India slipstone hones with flat faces and the edges radiused for curved / recurved edges of gouges and such. I'd think those would be ideal for this application.
 
annr said:
Wondering…Is this absolute? I feel I can see this problem with good glasses and proper lighting. I may not see the finest detail, but do see the problem and know when it’s no longer a problem —based on sight and cutting performance.

I also realize that as soon as I use the knife, the perfect edge is degraded. So I go for can’t see it and it works as intended with minimum force.
Click to expand...
I'm basically in the same place now. I can recognize by cutting performance what shape the edge is in and what's going on specifically, like issues with flimsy burrs that make cutting alternately OK on one pass through paper, but then slipping or snagging in subsequent cuts. That indicates a burr or foil edge that's moving around a lot under use. If it's cutting effortlessly and consistently through multiple passes though, that tells me the edge is keen and stable and good to go.

Having said that, until I learned the above, I did find some form of well-lit magnification to be very useful in confirming what was happening, when I initially didn't have a good sense of what was going on.
 
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