sharpining, burr on, burr off???

[minowevie]

Hi all, as some of you know, I am a beginner, and learning to shape , and sharpen my knifes. I am talking about chip carving knifes right now. so has any one did this. a friend of mine said I should draw a wire on the edge of my knife,(not draw, sharpen to draw it to the end of the blade and leave it on. hmmmmm. I am so confused, but have seen this on lathe tools also. leaving the burr on the edge. something about it cutting into the wood and not spitting it. I have been sharpening till it came off my chip carving knife. and still have problems with cutting . Ice sickles is what I am working on. so there is a lot of grain cutting going on there. could someone tell me how this works better. and if so. wouldn't that grind my knife down a lot? I got a new black Arkansas sharpening stone, and can get there fast. does this mean, I should leave the wire on and cut, then when it come off. should I make a new wire. sorry confused. Evie

[Simplyme]

Good to see you here on this site, I know you very well from the sister site for Scrolling........Sorry I can not help you because I have not even come close to being able to sharpen my tools......

[Curly Early]

Evie,
Your friend may know something I don't, but getting the wire edge is half the battle. After getting the burr, now the knife goes to the buffer at my house. I use a drill with a leather wheel and also a felt wheel on the Delta. I do notice others go to the stone or sandpaper often, but I do not find this necessary. I keep a piece of leather strap in my kit with compound on it and after 15 minutes or so of carving, I give my knife a few strops and go again. Before a carving session, I usually take the power buffer to the knives and gouges I'll be using that evening, then touch up as I carve by hand stropping.

[ironMan-Carve]

I don't claim to be an expert but I do know what works for me. I think you will find that it works for you also.

The basic concept is to keep sharpening the knife with finer and finer grits until the wire edge is no longer detectable. If you leave the wire edge on the knife, it will break off while carving and dull the knife.

Here is what I do; 1. if I have a really dull or damaged knife I will sharpen with a coarse grit until I get a wire edge. I then turn the blade over until I get a wire edge on the second side as well. I sometimes go back to the first side just to make sure I can consistently produce the wire edge while holding the knife at my desired angle to the stone. 2. I will then proceed to a finer grit until I get a wire edge again. 3. I repeat this process until I can barely feel the wire edge. You will notice that the wire edge gets finer and finer as you move from coarse to fine grits. By the time I sharpen on a black Arkansas stone, I can barely feel the wire edge. 4. At that point, I move from my finest stone (ie. Black Arkansas Stone or similar) to a leather strop. When using the leather strop, make sure to hold the knife blade at the same angle you held it for sharpening on the stones (or sandpaper, etc.). Once you have stropped the knife on the leather for a while, the wire edge will be so fine (if it even exists) that you will not be able to feel it. At this point your knife is very sharp and ready for carving.

Make sure you develop the wire edge on both faces of the knife before moving to a finer grit.

You will find that once you get the initial wire edge with the coarse stone, the process moves very rapidly since it takes very little effort to bring up a wire edge on the next finer grit. You must concentrate on keeping a consistent angle of the knife to the stone. A change to a steeper angle will bring up the wire edge quicker but it really works best if you keep the same desired angle. If you loose the wire edge while moving to a finer grit then move back at least one grit and work the knife until you can feel the wire edge again. This is important! Don't move to the next finer grit until you can consistently develop a wire edge (on both sides of the knife) on the current grit while holding your knife at the same angle that you started with.

With practice, you will soon find that developing and then subsequently removing the wire edge until it disappears on the leather stop is fairly easy.

There is another art to the science of sharpening - the best (relative to the hardness of the wood) bevel angle, and sometimes secondary bevel angle. But this is a subject for another time.

[dwlind]

Evie, I agree with ironMan-Carve, when I see the wire edge on my blade I know I am half way there, it's then off to the strop. I keep working on the strop until I polish the wire edge right off the blade.

Doug

[scooter]

Evie, I don't understand the benefit from leaving the burr on the knife. Seems to me it would only hinder an otherwise keen edge.

Perhaps your friend meant to leave the burr on... then strop it off?

S~

[xsailer]

The burr must come off and will if you continue buffing/stropping repeatably. Repeatably means rotating (if a knife then one side to other)the cutting edge contact to the buffing/stropping surface. What you're doing is bending this "burr" one way to the other so that it will break away just like a wire does if you bend it one way to the other. Adventually the burr which is so thin, it's like foil, will fall away leaving your extremly sharp cutting edge. Repeating you do not want to leave the burr on your knive/gouge cutting edge.

Whats happening is by you stropping/buffing one side to the other you are thinning and or bending over the length of the burr at the knive/gouge cutting edge. This action either breaks the burr edge or becomes so thin by your continued stropping/buffing that it can't hang on the parent material it falls off. Walla your cutting edge.

Hope I've helped and not confused.

[minowevie]

Thanks every one. I was so confused, I heard just leaving the burr on would help me shave the wood better. didn't' sound quit right. Evie

[sebastiaan56]

Hi Evie,

I found this paper very useful for understanding sharpening. http://www.bushcraftuk.com/downloads...nifeshexps.pdf lots of piccies which is useful for visualising the process. I use a linen glass for initial checking of edges but my eyes arent as good as a microphotograph.

[ironMan-Carve]

sebastiaan56,

That looks like a very interesting article on knife sharpening. It is a little technical and very long but seems to have some really good information. I plan to read it, little by little, as I can.

Steve