Stropping for burr removal

ejames13

ejames13

Basic Member
Joined
Mar 30, 2015
Messages
800
I’ve read so many conflicting opinions on this topic. It seems pretty divisive. Some people swear that if you need a strop to remove a burr then your sharpening technique needs work. Others say there’s no way to fully remove a burr if you don’t do some sort of stropping.

I’m looking for some answers from some of the experienced sharpeners here, particularly those of you who do professional sharpening. Do I need a strop, or should I be able to get a perfectly clean edge off of something like the sharpmaker medium stones?
 
You can get a perfect or very nearly perfect burr-free edge right off the stones. You can get there faster if you use a strop of some sort to finish. I finish all of my paid sharpening on a hard strop, even if its only a couple of passes. I always do my best to deburr prior to that though, I do not rely on the strop to remove burr but to do a final edge finish.

If your technique isn't on the ball or your strop surface/abrasive is not a good match to the steel, you can wind up with a less good outcome than just stopping on your last stone.
 
My answer would simply be:
"YES."

Or:
"Do what actually works best for you, depending on the situation and specific circumstance."

There comes a point in the development of sharpening skill, when a burr can be made fine enough on the stones, and it no longer matters whether it's removed by stropping or by some other means, like more detailed finishing work on a stone. OR, it can be made fine enough that it doesn't need any more work at all, and whatever's left will be easily stripped away in normal use anyway. As an example I see pretty often in my own sharpening: in the first one or two cuts into the edge of a piece of paper, the edge might catch or slip a little bit, due to a fine, thin burr that's 'hooked' into the paper (catching) or rolled over (causing slipping), after which that behavior disappears in subsequent cuts, because the fine burr gets ripped away in the process of cutting the paper.

It's true, SOMETIMES, that if technique on stones isn't quite as perfect as it could be, a strop with an appropriately aggressive compound can be an easier means to de-burr an edge. This is more apparent, and an easier fix with an aggressive strop, if the burrs are large and thick and easily detected with a thumbnail or felt while rubbing the edge on the pads of your fingertips. My favorite strop, for heavily-burred edges like this, is a hard-backed denim strop with something like white rouge compound, or any other clean-cutting, aggressively-polishing compound (aluminum oxide, SiC, diamond, etc). Really tough, thick & heavy burrs on very ductile steels like 420HC or VG-10 are easily removed by such a strop, and sometimes it's just too easy to clean up the edge this way, rather than doing some additional detail work on the stone, even if I know I can do it that way.

It's also true, sometimes, that if technique is already near-perfect on the stones, an edge can still be enhanced and made that extra 1% burr-free, by stropping on something appropriate to that job. If the cleanup on the stone was really that good, the stropping can be done on most anything, with or without compound, to make some small improvement. Bare leather, your jeans, paper or cardboard, wood, or even on the palm of your hand, is sometimes enough to break away the last feathery remnants of burrs, if they were thinned enough on the last stone used.

David
 
Last edited:
Use magnification to observe the burr, both in formation and for removal.
I like 10x loop and have Nikon wide field microscope variable 10x-80x.

Many techniques are valid, choose the best for your comfort,,, keep experimenting.
Mine is final removal on extra fine stone with very light pressure however, a thin hard leather strop with diamond powder is also very quick and efficient. I have a progression of 6 micron to 0.5 micron.

Soft strop with buffing past is not very efficient and may lead to rounding the apex.

Absolute worst is dragging through wood or cork,, this rips off the burr and leaves a rough edge,,,, not the clean apex we strive to obtain.

Regards,
FK
 
I sharpen many of my knives and don’t finish them on a leather strop. I think the strop motion is more important that what is used as the strop itself. Ive gotten great results progressing through my stones and removing burrs by stropping with each stone. By the time get to my fine finishing stone the burr is so small i can barely feel it. Very light pressure stropping motion then refines the edge. Yes a leather strop of some kind would finish the edge even better but its not necessary.
 
I never ever use stropping on utility knives and I sharpen a ton of them. Only exception are tools that NEED a polished and very closed edge, f.e. woodworking tools (chisels, carving knives, axes, ...) and razors. NOT because you can not deal with the burr, but because the very apex has to be closed --> polished. When you use stropping with compounds you take all the slicing aggression away. Fact.

The goal is to never have a big burr or even worse a feather edge from powered grinding left before the final honing. When you sharpen by hand then you need a good enough technique to minimize the burr before final honing. If you sharpen by machine you will develop a feather edge wich you have to cut off by sharpening by hand before final honing.

Never pull through wood or anything else to rip off the burr, you will get a very weak edge, even if you continue with stropping or somethimg else.

Br Oliver
 
Thanks for all the replies! Very helpful info.

I’ve never been able to get a completely burr free edge without stropping. I’ve probably gotten the closest with M390, presumably because it’s not very ductile? I use a leather strop with CBN emulsion 7 micron and 4 micron to do final burr removal. However, even after examining the edge with a loupe to verify the burr is gone, the edge is not very durable. After making a single cut through a few feet of cardboard the edge will no longer slice newsprint.
 
ejames13 said:
Thanks for all the replies! Very helpful info.

I’ve never been able to get a completely burr free edge without stropping. I’ve probably gotten the closest with M390, presumably because it’s not very ductile? I use a leather strop with CBN emulsion 7 micron and 4 micron to do final burr removal. However, even after examining the edge with a loupe to verify the burr is gone, the edge is not very durable. After making a single cut through a few feet of cardboard the edge will no longer slice newsprint.
Click to expand...

To what angle are you sharpening the edge? I ask, because it may be that a moderately stiff burr is largely responsible for the edge slicing newsprint before the cutting in cardboard. And after the cardboard cutting, the burr has possibly folded or has been stripped away, and the remaining edge geometry might be a little too wide for slicing newsprint, if the apex isn't perfect. In general terms, if you see a lack of durability in a paper-slicing edge, that's often the reason for it (a burr that folds after a few cuts or less).

Newsprint-slicing gets a lot easier at edge geometries of 30° inclusive or less (15° per side, or lower), even if there's a burr on the edge. The underlying, narrower geometry is what makes the difference, in maintaining decent or good paper-slicing sharpness after the burr has folded or been stripped away.
 
It requires good technique to remove a burr on the stone. Final stone for me is around 400 grit. I try on every blade to accomplish this. If it takes longer than it should I'll strop that area. The edge is burr free. DM
 
David Martin said:
It requires good technique to remove a burr on the stone. Final stone for me is around 400 grit. I try on every blade to accomplish this. If it takes longer than it should I'll strop that area. The edge is burr free. DM
Click to expand...

David, for the cases where you see it taking 'longer than it should' to deburr on the stone, do you see any common patterns in those cases? Certain steels, certain abrasives, etc?
 
HeavyHanded said:
You can get a perfect or very nearly perfect burr-free edge right off the stones. You can get there faster if you use a strop of some sort to finish. I finish all of my paid sharpening on a hard strop, even if its only a couple of passes. I always do my best to deburr prior to that though, I do not rely on the strop to remove burr but to do a final edge finish.
Click to expand...

^
This sounds to me like The Full Monty !
Perfection !

ejames13,
Some steel alloys are just a drag to debur. That said if you find the right stone then often you can do it right on the stone. As HeavyHanded said a touch on the strop after deburing adds that extra quality to the edge finish.
I guess, come to think of it, I tend to choose steels that debur nicely on my stones. Turns out many of those are very satisfying to use (cut accurately, feel good doing it and stay sharp significantly longer than many other less "super" steels).

It is fun for me to sharpen and see the micro bits of the bur come off on the stone.
It is NOT fun for me to see the dang bur just keep getting wider and flipping back and forth until I want to bite it with my teeth and rip it off like a hangnail.

Blades / alloys that are the latter don't get many miles in my little parade.
 
maximus83 said:
David, for the cases where you see it taking 'longer than it should' to deburr on the stone, do you see any common patterns in those cases? Certain steels, certain abrasives, etc?
Click to expand...
Yes. 440C is very burr prone. The knives I am handed can be in good to dismal condition. A recurve area on a convex edge is burr prone and working it off on a stone is slow. CPM154 is a dream to sharpen. It always comes out nice. S30V is somewhere in between. Commercial knives
are a lot of 420 and Sandvik steels they cut quick and sharpen easily. Unless they have damaged edges. i.e. nicks, rolled bevels, broke tips ect.. I see all types and wonder how they did that. All a good challenge in life and you need to be able to make it look real good in 8-10 minutes while they watch. DM
 
Obsessed with Edges said:
To what angle are you sharpening the edge? I ask, because it may be that a moderately stiff burr is largely responsible for the edge slicing newsprint before the cutting in cardboard. And after the cardboard cutting, the burr has possibly folded or has been stripped away, and the remaining edge geometry might be a little too wide for slicing newsprint, if the apex isn't perfect. In general terms, if you see a lack of durability in a paper-slicing edge, that's often the reason for it (a burr that folds after a few cuts or less).

Newsprint-slicing gets a lot easier at edge geometries of 30° inclusive or less (15° per side, or lower), even if there's a burr on the edge. The underlying, narrower geometry is what makes the difference, in maintaining decent or good paper-slicing sharpness after the burr has folded or been stripped away.
Click to expand...

I always sharpen to 30 degrees inclusive using the diamond sharpmaker stones. Occasionally I’ll do a 40 degreee microbevel with the medium stones, but usually I keep the same 30 degree angle.

Ive tried the high angle pass method to remove the burr, but that doesn’t seem to remove it. Still it flips back and forth even with a very light touch.
 
I'm a strop guy. I learned with woodworking tools before I sharpened knives. Inherited some great water stones too. Even with a 10000x stone there is something by using lapping films.

Woodworking chisels are taken down to 8000x and above. The final lapping is usually .5 microns or finer. Imagine taking a knife down to 30000x!!! I was taught that it was about squaring the edge. Carry a wire as small as you can, and then polish, lap, or strop.

Knives aren't precision tools like a chisel, but why not take that edge as close as you can to perfect. My knife strops are doped with either 1 or 0.5 micron paste.

If you're a science guy, woodworkers are taking their edges down below 0.5 microns= 500 nanometres. Daylight wavelengths are between 350nm and 750nm. When you get down to that point, the edge is a mirror polish because the imperfections are too small for light to refract in them. Next time you see a mirror polish, that guy was working finer than light waves.

Stropping isn't crucial, but if your strop is beyond your last stone do it.
 
ejames13 said:
I always sharpen to 30 degrees inclusive using the diamond sharpmaker stones. Occasionally I’ll do a 40 degreee microbevel with the medium stones, but usually I keep the same 30 degree angle.

Ive tried the high angle pass method to remove the burr, but that doesn’t seem to remove it. Still it flips back and forth even with a very light touch.
Click to expand...

Are you using the diamond only, when sharpening to 30 degrees? If so, are you finishing on the flats of the diamond hones, or on the corners? I ask, because the diamond should leave the edge relatively burr-free (compared to using the ceramics), if pressure is appropriately light. And the flats will further reduce the chance of burring as well, as opposed to using the corners, which focus pressure laterally against the edge, increasing the chance of rolling or burring issues.

If you're following the diamond with any of the ceramics, you might first refine the edge as much as you can on the diamond, then test-cut with cardboard & paper-slicing immediately after that, before continuing with the ceramics. That could tell you if most of the durability issues (or burring) is coming from the diamond stage or from any ceramics that may follow. It's generally easier to unintentionally generate stubborn burrs on the ceramics, which is why I suggest testing the edge straight off the diamond, before going to the ceramic.

If you're just using the diamond only, and seeing the issues with (lack of) durability afterward, I'd suggest going even lighter in pressure in the finishing passes. Lateral pressure against the apex is generally what's responsible for stubborn burring issues, as a whole. And burrs will usually be the cause of poor durability at the edge, unless the sharpening angle is just too extremely low (that's not applicable here, at 30° inclusive).

Going back to stropping, it sounds like the burr you're having issues with is pretty ductile (flipping back/forth and not coming off). If so, I like using hard-backed denim with a good polishing compound (Flitz, Simichrome, Mother's Mag, etc) or other, similarly aggressive polishing/buffing compounds in aluminum oxide, to remove burrs like that. If none of the other suggestions work for you, I'd try that next. Keep the stropping angle conservatively LOW, and the pressure very light, when using compounds like that. You just want to 'kiss the cheeks' of the apex when using it, for the best effect.
 
Last edited:
Obsessed with Edges said:
Are you using the diamond only, when sharpening to 30 degrees? If so, are you finishing on the flats of the diamond hones, or on the corners? I ask, because the diamond should leave the edge relatively burr-free (compared to using the ceramics), if pressure is appropriately light. And the flats will further reduce the chance of burring as well, as opposed to using the corners, which focus pressure laterally against the edge, increasing the chance of rolling or burring issues.

If you're following the diamond with any of the ceramics, you might first refine the edge as much as you can on the diamond, then test-cut with cardboard & paper-slicing immediately after that, before continuing with the ceramics. That could tell you if most of the durability issues (or burring) is coming from the diamond stage or from any ceramics that may follow. It's generally easier to unintentionally generate stubborn burrs on the ceramics, which is why I suggest testing the edge straight off the diamond, before going to the ceramic.

If you're just using the diamond only, and seeing the issues with (lack of) durability afterward, I'd suggest going even lighter in pressure in the finishing passes. Lateral pressure against the apex is generally what's responsible for stubborn burring issues, as a whole. And burrs will usually be the cause of poor durability at the edge, unless the sharpening angle is just too extremely low (that's not applicable here, at 30° inclusive).

Going back to stropping, it sounds like the burr you're having issues with is pretty ductile (flipping back/forth and not coming off). If so, I like using hard-backed denim with a good polishing compound (Flitz, Simichrome, Mother's Mag, etc) or other, similarly aggressive polishing/buffing compounds in aluminum oxide, to remove burrs like that. If none of the other suggestions work for you, I'd try that next. Keep the stropping angle conservatively LOW, and the pressure very light, when using compounds like that. You just want to 'kiss the cheeks' of the apex when using it, for the best effect.
Click to expand...

I generally move to the medium ceramics after the diamond. I’ll try sharpening only with the diamond and see what kind of results that produces. What level of sharpness should I be able to obtain when using only the diamonds?
 
ejames13 said:
I generally move to the medium ceramics after the diamond. I’ll try sharpening only with the diamond and see what kind of results that produces. What level of sharpness should I be able to obtain when using only the diamonds?
Click to expand...

Should be at least sharp enough and durable enough for both the cardboard cutting and paper-slicing afterward. Main thing you're looking for, is that the paper-slicing edge keeps working after at least a few cuts in cardboard, if not much longer. That'll prove the burring is no longer an issue, coming off the diamond, if it keeps cutting.
 
You must log in or register to reply here.
Back
Top