Removing burr and unequal sharp sides

[Zamfir]

So, I am having a brain fart here.. we make a burr, then go up in grit until the lats grit..recently for me it has been 1K plate. Some people say making a burr is bad because it has made a week and stressed part of the blade edge..

question 1:
After confirming the burr happens on both sides..is there something special I should be doing to remove the burr and then continue?

question 2: sharper on one side?
I was sharpening a cheapo kitchen knife, confirmed bur on each side, then moved on with alternating strokes and worked my way up in grit to 1K. Then I would feel the edge with my fingers on both sides and it would grab more on one side then the other. (similar to feeling for a burr but straight across rather than dragging fingers from spine up along the side to feel for the burr) makes me think I have a burr still hanging off to the side that grabs more (or something?)so I hit the side that side more until both sides felt to “grab at my fingers the same” when dragging them across in both directions. This made me think of some other times when I finished up a knife and it would shave good on one side but not as well on the other.. What does a feller do when this happens? So The blade feels nice and sharp and was for sure apexed..but one side saves and the other not as well. What is the right process to fix this..or better yet, how to keep it from happening in the first place?

Thanks!
-Eric

[Zamfir]

Part of my question is, if my blade feels sharp, and say I am holding it in my right hand with the blade edge facing forward and it shaves arm hair easily. The I hold it in my left hand with the edge facing forward and it will not shave as well. What does that mean I need to do to fix it?

So say I did the above tests, then put the blade back in the WE vise with the handle on my side of the vise and the tip pointing away from me, Which side do I need to work more on? What would be the best procedure to make sure my edges are cutting the same on both sides. Sometimes this happens to me and I just go at it again but with no real method. Looking for suggestions on a method rather than just attacking it again. …maybe just attacking it again is what is needed.. :unsure:

[CliffCurry]

Great question, I have seen/felt the same thing, also on several basic kitchen knifes & maybe a cheapo folder or 2.

Ive been running a block of wood(soft pine) for a couple swipes down the length of the blade in between grits, moving from hard pressure to progressively lighter passes as I get down to 1000 or so with good results. Without a scope(soon I hope) its hard to say for sure, but I believe this is folding over or knocking off the burr and it gets removed by next few passes at the next lower grit.

One of the first knives I sharpened before I had learned anything, apparently had a wire edge. Felt sharp, cut paper etc, gave it back to my buddy and he said after the first cut it was dull as a door knob. Arghhh, since then Ive been particularly hateful of burrs and minimizing/removal became a focus. :unsure:

[Ziggy]

I’ll bring up a burr on each grit.
I’m a fan of a cheapo paint stick for the coarse ones.
As progression goes up, smaller burr with lighter touch, also a lite final pass on each grit to push the bur as small as possible on the other side.
Once in the thousands, hard felt block.

Works for me in a number of situations.

[Zamfir]

so what exactly are you doing with the felt block and or piece of wood?

I can imagine the piece of wood you rub it up and down the blade edge with the wood flat like you were trying to cut through it, If the wood was stationary and the knife moved it would be like you trying to draw cut through the table or something right?

What is a felt block? And what are you doing with the felt block?

Thanks guys.

So if a blade will shave nicely on one side but not the other does that mean I have a burr still or is it something else?

[Ziggy]

I like using cheapo paint stirring sticks in the coarse stages.
I simply take the stick edge and run it over the apex, you see the metal come off and build up in the V of the wood.
Don’t try to do it all in one shat, and be mindful of the type of metal, all react differently.
Knife in vice, knife in hand, however your sharpening.

After the initial burr, I don’t build big one’s up as I have a good feeling I’ve reached the apex.
Feel it or loop it if need be.

As far as unequal sides, you should have them equal in the first stages of sharpening.

After around 600 or 800, I switch to the hard felt block for any fine burr removal, if its there at all.
Its online, just look up hard felt blocks. Just the right softness/hardness for higher grits and fine burrs.
Again, loop it if you’re not sure.

I find on weird metal that is not cooperating, I’ll sharpen on a particular stone, and deburr, and then give a few more passes with the same stone.
I find it assures me as the new fine burr feels crisp, and I’m not just pushing the old one from side to side.
As you go up in grit, you’ve established your angles and apex and the bur is minimal.
I even put some 1 micron boron on the cube, it glides easier and you can actually feel irregular metal as it doesn’t glide as smoothly.

This is just how I find it comfortable for me, everyone has their way.

As for one side sharper than the other, I’d guess you have a burr on the dull side.
Loop it, Q-tip it or do any number of things you’ll find on the forum that folks have done.
If you have a scope, you’ll see whats what.

Just my 2 cents.
Everyone skins the cat differently 🙂

[Steven N. Bolin]

I have a bad habit of biting my nails, so the “snagging on fingernail” method doesn’t quite work for me :unsure: And, in all honesty, I think I mistake micro-folds &/or teeth on the edge for a burr. That being said, I just try holding off on apexing the edge until reach the 600s. From that point I lightly drag my fingertips across the entire length of the blade to see if it bites. Then I proceed to see if it can puch-cut paper, etc.

[Mr.Wizard]

In disagreement with a few of the comments here my opinion is:

If one side seems sharper you likely have a burr pointing to that side, not the other.

Pulling the burr off with wood risks damage to the apex.

Your fingernails do not need to be long to use them to check for a burr. Drag the edge backward across the face of the nail in a “reverse shaving” motion, but at a higher angle, while carefully feeling and listening. With a fine edge if there is any scraping you have a burr. With a coarser edge one side will scrape more than the other if there is a burr.

[Ziggy]

In disagreement with a few of the comments here my opinion is:

Pulling the burr off with wood risks damage to the apex.

All relative to what you are working on and how you work on it.
I mention it as a tool that can be useful, if used properly.

A hammer can take out a dent or make one, all depends 😉

[Mr.Wizard]

Sharpeners with far more experience than I have use some variation of this method so it would be foolish to suggest that it has no value. Nevertheless it seems prone to misuse. If the burr is firmly attached to the apex it seems unlikely that it will come away cleanly leaving an even surface behind. If it is not firmly attached would it not come away in the process of refining the edge? When do you find that deburring on wood to the extent that “you see the metal come off and build up in the V of the wood” produces a better edge than “chasing” the burr or other methods?

Have you seen micrographs that show the result of deburring on wood?

[Zamfir]

I have a piece of wood and I am going to use it tonight on a bur. Just to see what happens..

that felt block is interesting! never heard of one..
http://www.chefknivestogo.com/harohadefebl.html

As you can see I recently started to ponder this thing called a burr. And we have varying opinions on how to deal with it..I like the discussion.
It was not until recently with the “unequal” sharpness that got me thinking about burr and microburrs and “wire edges”

So in all reality a very thin apex is not a bur..but when the knife gets used and it folds over to a side due to my wife cutting on a freggin plate rather than the cutting board..is it now a bur? Just because it is off to one side now?

This is the heart of what I am trying to understand..I hear people do not make a bur until so and so grit..or they just sharpen until the visible light is gone..or change up the angle for the last stroke or 2 or as you progress in grit the burr gets eaten away.. I have never done anything specifically to remove the burr, I just confirm I have one the whole length of the blade and confirm again on the other side..sometimes I get all worked up and feel like I need to raise a burr at 1K because..ummm dunno..I thought I messed up. or the angle moved..the blade did not pop as much as before on the previous grit..so I raised a burr..then on the other side..then back to alternating strokes..

Now..I am at 1K. My highest stone. Since I raised a bur on each side..now I am flip flopping this bur to get it nice and straight..is it still a burr? Should I have done something different to remove it..

I have just been pondering this and I would rather be sure the blade is good to go before I take it out. I have not attempted to remedy a blade that saves great on one side and not so great on the other yet..Just dealt with it. But if I can…MR OCD wants it better lol. Ohh man.. too much time at the in-laws..rambling now..

Please keep discussing..maybe something will knock loose in my thick head.

[CliffCurry]

I just imagine the edge apex as where the 2 angles meet in a theoretically perfect peak or point. Now imagine a tiny piece of tinfoil standing straight up on top. Thats what I think of as a wire edge, it will fold over first time it gets used on something harder then paper. To clarify I think a wire edge is just a centered burr.

Removing the burr/wire edge, then using edge leading strokes into the blade will minimize it reforming. I like the paper clip analogy, when you flex it back and forth eventually it gets weak and breaks, leaving a minute section of softer metal along the apex. Reaching the apex good, large burr bad. Thats my general thinking.

To go with my $4 60x hand magnifier(love it), Ive just found a direct source to a higher power usb microscope for $18. If it does half of what it should Ill be happy and share the results here for the rest of us on a limited budget with hungry minions to feed. 🙂

[Steven N. Bolin]

Such an all-inclusive rant. Love it. Honestly, thank you for speaking for me!

[Mr.Wizard]

So in all reality a very thin apex is not a bur..but when the knife gets used and it folds over to a side due to my wife cutting on a freggin plate rather than the cutting board..is it now a bur? Just because it is off to one side now?

This is the heart of what I am trying to understand.

now I am flip flopping this bur to get it nice and straight..is it still a burr? Should I have done something different to remove it.

I am not an expert so these are only my thoughts on the matter. I view a burr as any material that remains beyond the target geometry that you are machining. A very obvious example unrelated to knives:

The target geometry is a clean hole with a crisp corner. The burr is all the material that is proud of the upper surface.

I suppose that a rolled edge may be considered a burr and the author of scienceofsharp[/url] describes it that way. I took this thread to be within the topic of sharpening however, and rolled edges are usually use problems (extreme in the case of cutting on plates) unless one has poor angle control or is attempting to micro-bevel using too much pressure.

The goal of “chasing” the burr is not to “get it straight” as that results in a weak edge that does not last. Rather you wish to abrade off as much of the burr as possible and by pushing it to one side you expose it to abrasion in the next pass from the other side. Cliff Stamp advocates doubling the angle while making a very light pass on each side to directly cut away the burr.

This is an interesting video that shows the plasticity of steel that may help you think about how a burr is formed:

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[Zamfir]

Dang it. Should not read posts on the phone in bed. Your pictures of the holes helped to gel it a little. Thanks!

One thing i realized is all these Burr thoughts have popped up while sharpening cheapo kitchen knives.

So when Cliff suggests a couple light passes at 2x the angle do you then go back and do a couple more at the original angle? That would seem to make sense. OK. Time to turn the thinker off if I can.

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