Burr??

sjhong

sjhong

Joined
Jan 28, 2010
Messages
299
I've been told that to correctly sharpen a knife you have to raise burr. I still have a hard time feeling it in my knives or even understanding what burr actually is. Could anybody post a macro picture of a blade edge with burr?
 
Look up my thread "the burr" it will answer your questions.
 
knifenut1013 said:
Look up my thread "the burr" it will answer your questions.
Click to expand...

Thanks, how does burr feel to the touch? Let's say I slide my finger from spine to edge on the blade, would it feel like something is trying to scratch the skin?
 
Rough, but as they get small they become harder to feel and are usually found easier under bright light.
 
sjhong said:
Thanks, how does burr feel to the touch? Let's say I slide my finger from spine to edge on the blade, would it feel like something is trying to scratch the skin?
Click to expand...

Do you have a fingernail? If so, then running your nail from spine to edge will tell you if you have even the smallest burr. The burr will 'catch' your nail. A large burr will stop your nail completely and a small on will be only enough to just 'feel. If you want to really know what it feels like, take a $3 knife and scrub one side only against a coarse stone or sandpaper for five full minutes, holding the blade at a very steep angle. You should raise a burr large enough to catch your entire finger, not just your nail!

The burr is a very thin strip of metal at the very edge of the blade that has been rolled over to the opposite side from that which you are sharpening. When you turn the blade over and do the other side, the burr gets scrubbed off that side, and eventually forms on the other side. If you are alternating sides on each stroke, you will NOT raise a burr.

Stitchawl
 
stitchawl said:
Do you have a fingernail? If so, then running your nail from spine to edge will tell you if you have even the smallest burr. The burr will 'catch' your nail. A large burr will stop your nail completely and a small on will be only enough to just 'feel. If you want to really know what it feels like, take a $3 knife and scrub one side only against a coarse stone or sandpaper for five full minutes, holding the blade at a very steep angle. You should raise a burr large enough to catch your entire finger, not just your nail!

The burr is a very thin strip of metal at the very edge of the blade that has been rolled over to the opposite side from that which you are sharpening. When you turn the blade over and do the other side, the burr gets scrubbed off that side, and eventually forms on the other side. If you are alternating sides on each stroke, you will NOT raise a burr.

Stitchawl
Click to expand...

I use my finger nails while looking down the tip of of the blade like one would look down the barrel of a gun, but slightly offset to see the edge bevel very closely. Then you can run your fingernail across the edge bevel face and see when its going over the edge. You can also use all sorts of pieces of plastic to help with this; I find that a piece of a shattered CD works really well.

I think it's harder to feel the burr with a fingernail at lower grits, because the rough scratch pattern in the edge bevel will kind of obscure your results. So what's better to do is just brush right down on the very edge and see if it catches. Doing this up close and with light has worked best for me, because even if you don't feel it, you will push off the burr and it will shine in the light. That way you can catch a burr much earlier on, which is an advantage because it will reduce your livelihood of making a wavy edge.

With a very rough grit, having some kind of cotton ball or q-tip material, or maybe even just a cotton t-shirt to wipe the edge off on will assist you, because the burr from a coarse edge will catch those fibers very readily.

It's hard to catch a burr for me on the skin because my finger tips are very calloused, but in any case typically a burr feels like a small bump, and when they get smaller on finer grits I really can't feel them without my fingernails.
 
You can usually see the burr under very bright light (I can't emphasize "bright" enough; indoor lighting won't do.) Rotate the blade around various angles, and if you see any highlighting on the very edge, then you have a burr.

The second method of detection is to drag your finger nail down the bevel, almost parallel to the direction the edge points. A burr will be on one side or the other. If on one side you see a lot of your nail's fiber come off but not on the other side, then you probably have a burr.
 
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