The burr

Got some decent shots of burr creation from added pressure while using a DMT EEF 3 micron diamond hone. All pix at 400x

Burr free before
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Pressure added (the weight of the blade plus the weight of my hand)
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When a knife is reprofiled or a dull knife resharpened, I've always needed a burr to tell me when and which parts of the blade still require sharpening. I don't see how you can fully sharpen the entire blade without the advice of a burr.

Typically, on a dull blade, the tip or the middle part of the blade -- the part most used for cutting -- is much duller than the rest. I don't see how you sharpen the dull portion without raising a burr on the rest of the blade, unless you sharpen only the dull portion, which will lead to non-even wear.

And on reprofiling a blade, you'd need almost flawless technique to get the entire edge sharp at the same time.

So I always try to raise a burr, except on an already sharp knife that I'm simply tuning up, which is most of the time. The burr is not difficult to remove, and it tells a story.
 
I'm no expert (or even a journeyman for that matter) but I did pick up a trick from the free Murray Carter vids on YouTube. After honing, lightly cut through some soft wood or cardboard a few times to knock the burr off, then hone again.
Works for me.
 
When sharpening I use a burr to tell me things too but I can also remove the burr with a light touch and careful strokes as I'm finishing up with my stone. no special strokes or technique just less pressure.
 
i believe i saw the same video jfn saw on youtube, and i sometimes do that when i am having trouble with a burr
 
Tip for keeping your bevels kind of even when coarse grinding. Pick a number of strokes. Any number is fine. Just for exsample 30 strokes. Do 30 on one side then switch to the other side and do 30 on that side. Keep doing this until you get a burr instead of just doing one side at a time. This will keep your edge centered for the most part.
 
In response to the filet knife comment: you said a coarse edge would work better for fileting fish, but i've always found that a highly polished edge works better and lasts longer for everything but the initial back cuts. For the back cuts i've found it works best to keep a second knife around with about a 400 grit edge on it and about 20-25 degrees per side angle. Switching between the two lets me clean dozens to hundreds of fish between sharpenings depending on the quality of the knives.

Anyhoo, great thead! I learned a few very useful things from it :D
 
Just came across this thread.Good stuff knifenut1013,very informative,Thanks:thumbup:
 
jfn said:
I'm no expert (or even a journeyman for that matter) but I did pick up a trick from the free Murray Carter vids on YouTube. After honing, lightly cut through some soft wood or cardboard a few times to knock the burr off, then hone again.
Works for me.
Click to expand...

I have a similar question: in a video on sharpening kitchen knives, mention is made of using a synthetic cork "to knock the burr off" at 39 seconds, and then demonstrates at 6:09 and 11:00 minutes.

[video=youtube;riey-QAyFAo]http://www.youtube.com/watch?v=riey-QAyFAo&feature=player_embedded[/video]

Opinions on this application, please?
 
Personally, any method of burr removal should be verified with careful visual inspection, in my experience dragging a burr edge across just about any surface yields very inconsistent results (works great sometimes, other times that burr ain't going nowhere). I guess the real question starts to be "is there a point at which chasing the burr yields diminishing returns?" If the base of your burr is down to what a reasonable apex might be (2-3 micron or less for most edges), then the burr itself when it falls off, might actually leave behind a finer/ better cutting edge. Chasing it to extinction could lead to excessive stropping or microbevelling that might actually leave you with a less acute edge...Maybe.

I should attempt some micrographs for example, but I know some of the continuous burrs I've seen at 10x (barely, but visible), when viewed at 640x appear to be much more fragmented and no more than a micron or two of metal leaning over the grind at some of the "low" spots here and there. I'm an obsessive burr remover, but lately have been considering the pros and cons of being overzealous. The base of some of these burrs is certainly down to a micron or less.
 
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Unless the burr is very large, like from over doing it on a belt sander, I have not found drawing the edge through cardboard or wood to be effective in removing a burr. If the burr is very stubborn, I'll draw the knife into the stone very lightly for one or two strokes. This gets rid of any burr, but I have to go back and do a final sharpening, since I've essentially cut the edge off. This is usually just a few strokes.
 
I know opinions vary on this subject but after all this time I still stick with my thoughts on the burr.

A burr can be broken by running the edge over something but if the edge is not taken back to a stone then you will likely be left with a damaged edge with folded burr remains. This is personally not a method of burr removal I would suggest unless you understand exactly what you are doing and know how to follow up.
 
It seems to me that the best way to deal with a burr is to not have one. I've read about the burr a lot but never experienced it on any of my knives until recently. (And I've probably not experienced it because I didn't know how to detect it or I wasn't looking hard enough.) I bought a cheap used CRKT that had some chips in the edge so I used a coarse DMT stone as a file on the edge to try to get it close to a reasonable edge. In the process I developed a big burr which at first was reassuring because that told me that I was able to take off enough material. Then I started working with it on my Sharpmaker and got a reasonable utility edge.

I've done some sharpening on very dull blades and I used a magnifier and bright light to see if my 2 edges were meeting. If there was still light reflecting off of rounded or flattened material at the apex then I knew that my 2 edges had not met yet. Then I was only using the sharpmaker and it removes material pretty slowly.

But I'm still not an expert at achieving the final sharpening and once I think an edge is starting to get sharp I can work on it for a long time and not get any better. I've wondered about the amount of pressure to apply, particularly since the sharpmaker only touches the edge at tiny points and this could concentrate the force on the blade edge. Maybe all I'm doing is moving the burr back and forth. Maybe I need a better way to detect the burr.
 
knifenut1013 said:
I know opinions vary on this subject but after all this time I still stick with my thoughts on the burr.

A burr can be broken by running the edge over something but if the edge is not taken back to a stone then you will likely be left with a damaged edge with folded burr remains. This is personally not a method of burr removal I would suggest unless you understand exactly what you are doing and know how to follow up.
Click to expand...

FWIW, I agree with what you wrote many months back. Especially the comments on removing the burr. I find the burr I raise a good start for shaping and reprofiling an edge, or repairing a damaged blade. It is only a starting point for a finished edge, part of the process.

I don't treat the burr like many do, and like most have my own method of dealing with it when sharpening. That's why I appreciate the fact you left the door open in your comments.

I use a Lansky system, and have for about 25 years or so (more?) since a local folder maker told me he used it to "set" his edges and profiles. It took me a while to get the hang of it, but now it is a favorite.

Burr removal on the Lansky system or just about any other guided system from the lower cost equipment on up is accomplished by cutting off the burr, not breaking it off. I roll over a burr so small I can't see it, but can detect it only with a slight catch on my fingernail. When finalizing the edge, I roll this tiny burr along the length in the successive grits, and when I flip over the knife and go to the next grit, I carefully cut it off, going against the blade edge with very light pressure.

I quit rolling the burr over around 600 grit, and start to polish the edge. By the time I used their "Ultra Fine" white polishing stone, the hard steel knives will have a mirror like reflective edge that is nasty sharp. If the knife is one of my slipjoints, they all have a blade selected to cut a notch in the very fragile end of a good cigar. After the Lansky, I usually strop that one blade with some green compound to bring it up to mirror. That's the only time I am not cutting steel off the blade, and the only time I am pulling the edge when sharpening as opposed to pushing it.

That being said, my work knives get the worst of it. No matter the edge, cutting/trimming sheetrock, cutting through a shingle, removing old, hard adhesives, etc., ruin an edge in no time. My work knives are usually a medium quality stainless, and they get a free hand sharpen on my chef's diamond rod at 600 grit. A few swipes after cleaning off tar, caulk and adhesives, and they are up to speed again in a minute or two. To me, this lower grit works better as that lower end stainless really seems to work better on the job when it is a bit toothy.

Robert
 
Perhaps I have given up. The more I read, the more inadequate I feel in my sharpening skills (minimal as they were) The illusury Burr being my greatest nemesis.
I have resorted to the sharpie "ticks" and then sharpening until the are gone to the apex then I move on to the next finer grit and rinse/repeat.
I dunno. I do not blame my WEPS, I believe the results are me and whether I had uninterrupted time in my shop. It seems like any time I go down there and decide to "treat" myself by sharpening a knife, the wife comes down because the dog just ate the cat or it's time to paint the bathroom....
I decided to sharpen one of my new (already sharp) Hinderers last night. Ended up not as sharp as it was (Nice)
Time well wasted and frustration instead of relaxation at the end of a tough day.
I would pay dearly for the most Fool Proof method OR a step-by-step "Do This" and there is no way you will screw up instruction book.
It seems to me the challenges in sharpening are:
- Correct/Consistent angle
- Proper pressure
- Mastery of the invisible Burr
I think the WEPS was/is a great invention trying to solve most of the pitfalls BUT it is time consuming (which I don't mind) but my results still vary.
The search for sharpening nirvana continues.
 
Usually more practice with time to think about what you're doing and some manner of detecting it (such as a magnifying lens or a consistent testing material to cut) will help. Going from one system, method, or style to another usually involves reinventing the wheel.
 
There are several things in life I have heard of their existence. People talk about them.... I've never seen them.
They have names, general locations, supposed reactive properties - still have never seen one.
Been searching, maybe even found them (occassionally) by accident.;)
The Burr is one such example.

Dolores! is that you?
 
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