Using a stropp to diagnose or get a burr

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Aug 14, 2019
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When I sharpen with a stone, the burr forms on the opposite side every time as expected. When I follow with a hard strop, trying to even out the burr it seems the burr forms on the same more times than not. That's confusing. What or where should I feel the burr when stropping, when do I stop or change to the smooth side of the strop? When should I know the stropping process is done? When should I quit on the rough side vs. go to the smooth side of the strop? (It seems that if I don't get a real refined clean edge from stones, while the rough side of the strop does improve the cutting, going to the smooth side dulls the knife again.).
 
Mod will probably move this thread to maintenance. You have to pass back and forth and you will feel the burr when you press it against a finger nail it will bite on one side of the knife and not the other. You have to do that for a while to weaken the burr and often times it won't break off. Like Case knives for whatever reason have pesky burrs. The next step can be to break the burr by sharpening against a fine stone at an obtuse angle say 45 degrees very gently.A few passes on that, then back to a fine stone then a chef's knife hone or leather strop or cardboard usually does the trick for me.
 
I always eliminate the burr before going to the strop. The strop is for refining the final, burr-free edge in order to get a noticeable increase in sharpness.

The best way I've found to eliminate the burr is with light and very short (no more than a quarter inch), edge-leading strokes on the stone. Because the burr leans to one side, a short pass with the stone on that side will cut off the burr.

If you make the pass too long, you will just recreate the burr on the other side.
 
Clarification: What side of the blade should I feel a burr forming when stropping? The same side as I strop or the opposite side (as with sharpening)?
 
I always eliminate the burr before going to the strop. The strop is for refining the final, burr-free edge in order to get a noticeable increase in sharpness.

The best way I've found to eliminate the burr is with light and very short (no more than a quarter inch), edge-leading strokes on the stone. Because the burr leans to one side, a short pass with the stone on that side will cut off the burr.

If you make the pass too long, you will just recreate the burr on the other side.
Great advice.
 
Clarification: What side of the blade should I feel a burr forming when stropping? The same side as I strop or the opposite side (as with sharpening)?
It should form the same as when on the stone, the opposite side. Stropping isn't all that different than sharpening. It just used a different stroke and usually a softer backing. But its abrading the steel the same.
 
Clarification: What side of the blade should I feel a burr forming when stropping? The same side as I strop or the opposite side (as with sharpening)?

You shouldn't really form a burr when stropping because you're removing almost no metal. You don't get the plasticity (smearing) that you do with stones.

If you have a burr, stropping is more likely to straighten it out, making it appear as if the apex clean of a burr. But in reality, the very edge will be weak because it's made up of the weakened metal of the burr. That's why I like to ensure that there is no burr left before I strop.

If you really want to get into the weeds on burrs, check out this link provided by Garry3 in another thread:
http://knifegrinders.com.au/Manuals/Knife_Deburring_book.pdf
 
You should not be forming a burr when stropping. If you were to however, it would form on the opposite side but again, you should not be forming one at all.

You cannot strop a knife into sharpness.

Stropping can be controversial but most see it as either a method to remove the slightest remaining burr left from the actual sharpening and/or as a method to highly refine the already sharp apex.

As @DeadboxHero so accurately says, strops enhance but they do not create.

I personally am in the both camp - I strop to ensure burr removal and enhance the edge. I also strop for maintenance but that's a separate discussion.

I think the common thing is to put your compound of choice on the rough side of the strop and leave the smooth side bare. The rough side should do the de-burring and the smooth side the apex refinement. There's no hard rule here though.

I do not increase the apex angle for burr removal. You should be able to remove the burr at the same angle you sharpened or really close to that anyway. Increasing the angle is putting another bevel on the edge. The roughness of the strop will do the work.

If you don't already have one, I highly recommend you get a 10-20x loupe. A lighted one is better but not necessary. Don't guess at what is happening, see it. Use a marker to mark the edge of your knife and sharpen until the marker is full removed and you can see and feel a burr on the opposite side. Some steels can have a very slight burr that is hard to see but you should feel it. Then do the same on the other side. The I like to do alternating edge-leading, very light strokes on the stone for burr removal. Same angle as the sharpening angle, real light, five or ten times.

Then very light edge-trailing on the strop, maybe 1-3 times. Same angle as the sharpening angle.

You could be rolling wire edge (burr) back and forth or rolling your apex over or you might not be sharp off the stone. And don't move up in grits until your sharp off the first stone you start out on.

There's not a lot of info to go on, but the fundamentals are the same.
 
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I have found it's best to remove the majority of the burr on your final stone. Ultra light pressure, mostly edge leading, although occasionally some quick back and forths with almost NO pressure does the trick. Removing the burr was by far the hardest part of sharpening for me to get the hang of, and I'm still working to get better at it all the time. Learning to hold your angle with no pressure can be difficult. I always finish on a strop ot two, to clean up any little bits of burr left over, and to realign the apex, but I never want to form more burr on the strop.
 
if I have a burr that is stubborn I found that lightly drawing the blade over scrap wood or firm cardboard ... a cutting motion but with very minimal pressure ...

if that doesn't work ... a couple light passes on the stone at a bit more obtuse angle ...
 
I like to strop regularly on an old leather belt as I go, and try to prevent the formation of any kind of half decent sized burr. If that doesn't work, and I do get a burr, I'm with JJ_Colt45, I will actually cut some cardboard with the knife and then go back to sharpening. This time paying a bit more attention to my stropping! You will need to roll the knife slightly away from the direction of motion on the strop, almost as if you were trying to get a convex edge, using the old sandpaper on the mouse pad trick.
 
When I sharpen with a stone, the burr forms on the opposite side every time as expected. When I follow with a hard strop, trying to even out the burr it seems the burr forms on the same more times than not. That's confusing. What or where should I feel the burr when stropping, when do I stop or change to the smooth side of the strop? When should I know the stropping process is done? When should I quit on the rough side vs. go to the smooth side of the strop? (It seems that if I don't get a real refined clean edge from stones, while the rough side of the strop does improve the cutting, going to the smooth side dulls the knife again.).

Chances are, the burr you're feeling on the 'same side', when stropping, is just the burr that's leftover from the stone. It's staying on the same side of the edge because the strop isn't affecting it much, if at all. It's unlikely the strop by itself is forming a burr; this almost never happens on a strop, nor should it, if everything's being done correctly. And depending upon what compound you're using on the strop, if using any at all, the strop may not be doing enough to remove or reduce the burr left by the stone. This can happen if the burr left by the stone is fairly thick or large.

A tough, thick burr leaning to one side of the edge will also scrape leather and/or compound (if used) from the strop, much like your fingernails would collect stuff underneath them if you were to scrape the strop with them. You'll see scraped 'tracks' left on the strop, if that's happening. That's an easy way to see if there's a burr there in the first place, and also an easy way to tell if it's actually being reduced or flipped to the other side. If you're not seeing it reducing or flipping, that's telling you the strop isn't able to do enough by itself. That's the cue to take the edge back to the stone for some much lighter edge-leading passes, to thin & weaken the burr. After it's sufficiently thin & weak, then a strop can do a better job removing what's left of the burr.
 
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You shouldn't really form a burr when stropping because you're removing almost no metal. You don't get the plasticity (smearing) that you do with stones.

If you have a burr, stropping is more likely to straighten it out, making it appear as if the apex clean of a burr. But in reality, the very edge will be weak because it's made up of the weakened metal of the burr. That's why I like to ensure that there is no burr left before I strop.

If you really want to get into the weeds on burrs, check out this link provided by Garry3 in another thread:
http://knifegrinders.com.au/Manuals/Knife_Deburring_book.pdf
Thank you for the advice and the link.
 
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