Burr is kicking my butt

nozh2002 said:
BTW about "idiots" - 30 passes or something like this is what was recommended on Sharpmaker instructions (actually 20 for each side).

Thanks, Vassili.
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Vassili, as HH pointed out. The key is not the 30 sec. (seconds by the way, not strokes :) ), but the statement "no matter what state the edge was in". 20 strokes on the Sharpmaker are not going to help much on a really blunt edge. My bad on your technique. I thought you were using another diamond stone in between.

The ceramic rods start at the same particle size, but they are not packed more dense but they actually deform and fuse during the sintering process. Depending on the sintering process they can deform more or less. And AFAIK they are 35 micron particles in the "green" state (before sintering).

I don't think sharpness is only depended on grit size. Whether you finish on 4 micron or 1 micron is not the sole parameter here. I think, how many strokes you take on the final step, how hard you press, how large the gap to the previous grit are all important factors. I know, that if you go from 700 to 10000 (or even 350 to 10000) or 3000 to 10000 you get a completely different edge. On the ceramics, I would also expect that it would make a difference how recently you have cleaned them. And lastly of course, what steel you are honing.
 
I learned about burrs in elementary school sharpening points onto Popsicle sticks. Us kids would rub these flat wooden sticks on cement to create a spear point. Some kids would do a very quick job grinding at 90 degrees to produce an edgeless fence picket contour. Some others would put a slight side bevel on their sticks at about 45 degrees--they would produce a significant burr of residual wood fibers. I had some experience sharpening steel so I would try for about 30 degrees per side and I would get enormous burrs.

Most of our work had been done using back-and-forth grinding strokes. We tried using only edge-trailing strokes and that didn't work at all. We tried edge-leading strokes and it didn't make a lot of difference. We tried super-elevating our grinding angle and that only seemed to help when we used light edge leading strokes alternating sides. Even that didn't work well using cement. If we got a hold of some real fine sandpaper it cut more effectively.

Some of us got frustrated and attacked the edge by sort of slicing with the edge perpendicular on the cement. This got rid of the burr and the edge. That forced you to revisit your sharpening, but it worked. I had a pocket knife and could just slice the burr off (this is how I've often seen it done in the machine shop), to me this seemed like cheating. I had often just sharpened Popsicle sticks with a pocket knife and that wasn't what we were trying to do. Now I see how this points you to a sharp abrasive as part of the solution.

Anyway, I have seen burrs that were up to about 0.1 inch long. I watch them flop from side to side as I tried to remove them by honing at a constant angle with coarse or fine abrasive. I always had to dramatically change my angle of attack or my tool to get rid of these pesky burrs once I created them. One thing I learned was that if I did all my work at low honing angles the burrs got extremely long and recalcitrant. I decided that I needed to precontour my blade to an edgeless picket fence shape before starting to hone at a lower angle. Next it helped if I gave up back and forth honing strokes before I got close to the intended "edge". At that point I would start careful edge-leading strokes on alternate sides until I just started to get and edge. At this point I needed a better abrasive. Cement was to rough and varied in hight. If I used sandpaper I got further along. If I created a burr at all I was in trouble. I had to superelevate the angle dramatically and work extremely carefully or sacrifice the edge. I might need to just sand the edge a bit round with lengthwise strokes to shed the burr. Then go back to honing.

Anyway, burrs don't drop from the clouds or form like morning dew on your edge. They are unremoved material left by the honing process. In soft metal you might get a little bit of material that has been pushed from close to the edge out to the apex of the edge, but not generally with blade quality steel. Mostly what happens is that as you hone near the apex of the edge (at a low honing angle) material at the edge is pushed away from the hone rather that getting caught and cut by the honing grit. Some escapes by elastically flexing away from the path of the hone and some escapes by plastically bending out of the way. My impression is that the material that plastically bends away from the material is what a straight blade manufacturer would call a burr and the material that elastically bends away (to spring back more or less inline with the edge) is what would be called a "fin" in straight razor terms. Both of these are too weak to be desirable on the edge of a knife. To cut these off you need to super-elevate your honing angle and stroke carefully either lengthwise along the edge or with edge-leading honing strokes. I generally don't use the lengthwise approach with a knife because I don't want striations in the steel parallel to the edge (for strength reasons), but this should work. I do my best to minimize burr formation in the first place and use super-elevated edge-leading honing strokes preferably with a sharp abrasive. I like an ultra-fine diamond hone as my primary deburring tool.

I'm not sure how stropping works on steel. I think it depends on partly abrading and partly ripping off the burr. Since a strop is soft it will partly round off the edge when it uses abrasion. When it tears off the edge through friction it leaves it more irregular than you might expect. I like the control that I get with edge-leading honing. I like to strop after the burr is removed. That is what is recommended by the straight razor guys. I try and emulate their low angles so I borrow their techniques.
 
Since Jeff needs to have his edges pass the toilet paper slicing test just to be good enough to carry I would guess hair whittling may just be dull to him.

Mike
 
I am old and my hair is extremely thin. I also live in the extremely dry environment of 7,200 foot elevation. It is hard to whittle hair that is thin and dried out, even using a straight razor. I usually use toilet paper as a test medium when I go beyond easy shaving. I take toilet paper and pierce it with my blade. Then I see that I can slice it without tearing using a slightly transverse drawing cut. Some steels this is a pretty straightforward test of how thinly I have profiled the edge. On some stainless I have to strop using submicron diamond grit to achieve this performance.

By the way. In the past I have found it easy to whittle hair with burred edges. When you strop a burr you often don't remove it, you just groom it. Gentle stropping can simply bring a burr into alignment with the edge. It will shave or whittle hair OK, but it will not last very long if you cut anything substantial. It has an extremely fine, but very weak edge. The fine edge is simply an erect burr (and everyone knows that an erection doesn't last all that long). One of the reasons that I stopped addressing burrs by stropping is that I found that it covered over cases where edges were weak or burred.
 
Jeff Clark said:
I am old and my hair is extremely thin. I also live in the extremely dry environment of 7,200 foot elevation. It is hard to whittle hair that is thin and dried out, even using a straight razor. I usually use toilet paper as a test medium when I go beyond easy shaving. I take toilet paper and pierce it with my blade. Then I see that I can slice it without tearing using a slightly transverse drawing cut. Some steels this is a pretty straightforward test of how thinly I have profiled the edge. On some stainless I have to strop using submicron diamond grit to achieve this performance.

By the way. In the past I have found it easy to whittle hair with burred edges. When you strop a burr you often don't remove it, you just groom it. Gentle stropping can simply bring a burr into alignment with the edge. It will shave or whittle hair OK, but it will not last very long if you cut anything substantial. It has an extremely fine, but very weak edge. The fine edge is simply an erect burr (and everyone knows that an erection doesn't last all that long). One of the reasons that I stopped addressing burrs by stropping is that I found that it covered over cases where edges were weak or burred.
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Can you explain more on how to do this toilet paper cut? How to hold and under what angle to cut... Is it like usual paper cutting test. I like to learn how to do this if it is harder then whittling hair (I am not sure how dry is air here - I have usual slavic (Russian) hair, can not say how thin is it). And what brand of toilet paper?

Now I do not think that I have burr - burr can shave but I doublt that burr will whittle hair. I do not really stropping but polishing - meaning I spend quite some time not few strokes. Also if you see my tests - it keep sharpness after cutting manila rope for some time not loosing sharpness as this happen with broken burr.

Thanks, Vassili.
 
Here is some info from Sal on the Spyderco forum concerning the composition and grit rating of the Spyderco stones:

All of the ceramics use the same micron size (15-25). the different grits are created by different carriers, different firing techniques and diamond surface grinding

We've spent a great deal of time trying to determine grits for our stones. The manufacturer has also worked with us, to no avail. A guess seems to be best.

Most abrasives are measured by the grit size used in the matrix. Our ceramic doesn 't work that way. Grit size is constant.

We've tried to compare scratch patterns as Cliff mentioned and this is probably the closest, but nothing that we can say "This is blah blah". Then the Japanese water stones jump into the equation and suddenly there is whole new set of numbers.

So where we end up is:

Our diamonds are a 400 mesh (measureable). (600 on the Duckfoot)

Our gray stone is "medium". (Same material as fine but different carriers and heat treat).

Our fine stone is fine.

Our extra fine is a surface ground fine.
http://spyderco.com/forums/showthread.php?t=31188
 
Concerning burrs, I haven't seen it mentioned that they can be different in how they behave. Some are fragile and crumbly. They can be stripped off or wiped off by running the edge lightly through wood, stropping on felt, or taking light, elevated strokes on a hone. Others are more solidly attached. If I wack away at Buck 420HC on a sharpmaker, I always get a burr that can be bent from one side to the other but impossible to remove. It is deeply rooted and won't break off or flake off. I don't get this result on waterstones or DMT's. I believe it it is because the DMT abrasives are sharp and don't bend or deform the edge but rather just shear it.
 
I am not sure is it exactely what Jeff means. What I was able to do so far - I pierce it with the blade, but it was not clean straight cut, I just make like a hole inside piece tearing it up. Then inside this hole I was not able to do long clean cut, but with kind of picking slight short move I have 2-3mm cuts on the edge of the paper inside this hole. But it is not like usual paper slicing test.

Is it what are you talking about?

Thanks, Vassili.
 
I am so flippin' confused right now...

I thought a burr was the desired outcome when you are using the coarse stones, then you grind the burr away on progressively finer stones. I was happy last night because I got my first visually discernible burr.

I should not have read this thread.
 
Ha! This is fan!

I am not sure how close it to your test. What I start doing instead - is holding roll in left hand with foot or two of paper free hanging, with right hand I hit free hanging end of paper with slicing move - touching paper not with tip but edge only.

If it hair whittling sharp it make clean cut - if it not so super-sharp it kind of cut and tear it off, if it is not so sharp - not cut at all.

Well this is bit more dangerous then whittling hair I guess.

I'll post some video, later.

Thanks, Vassili.
 
dan97526 said:
I am so flippin' confused right now...

I thought a burr was the desired outcome when you are using the coarse stones, then you grind the burr away on progressively finer stones. I was happy last night because I got my first visually discernible burr.

I should not have read this thread.
Click to expand...

I guess there is just two schools in sharpening, I am raising the burr until I have visible all over edge length - I look for reflection on high light - it looks like bright line all over edge. I may not exist but then appear in few sharpening moves, so I doubt it is over-sharpening, but rather some material being pushed out due to high pressure on the very edge.

Then I chenge side and change stone after I have it on both sides. Stone with higher grit will remove old burr and create smaller. Then it will be removed with intense polishing (it is not 3-5 strokes). It does not exist on the edge - until it is non visible with x400 microscope.

It may be different theories behind, but I have my results, which is hard to ignore. Also it is pretty easy to follow this procedure to get stable excellent results.

Thanks, Vassili.
 
I was never good at the tp test, this is Charmin ultra strong, double ply with some diamondweave something or other. The cuts look so fuzzy :(




I find that any pressure tears the paper, I pretty much just pull the blade and let it lower when the paper cuts. The larger pic is six slices, about 3 inches in length, the second is two, about an inch. The rest are about 3/8-1/2" long.
 
See what I mean about clean toilet paper slicing being tougher than hair whittling, especially the way Jeff does it by piercing through the paper first (at least it is for me)? I only do 3-5 passes per side to microbevel an already burr free edge (as I described in getting a hair whittling edge with ceramics earlier), as verified by a 60-100X lighted scope. I verify under magnification that I have not formed a new burr, and if I did then I raise the angle like Jeff has said and follow his method for deburring. If it is good enough to work for him it is better than good enough for me, though many do it differently. Now I just need to practice to where I can get knives close to as sharp as Jeff gets them.

Mike
 
Here it is:

http://www.youtube.com/watch?v=tgJSPLVF2Wc

Is it the right way to do this?
Is it clean enough? I get bit cleaner result but without camera, of course...

I prefer whittling hair - this one is more about performing test skills then sharpness - holding paper right way, move blade right way...

Thanks, Vassili.
 
Well, I don't do the little sawing actions. I have no idea how Jeff and others do it, but when piercing the paper, I just push the blade through slowly, this tears the tp a little while/if the spine and edge are wedge shaped in profile. The cut cleans up when the edge and spine are parallel (or the spine is convex to the edge) and not forcing the tp apart. After making it to the handle, I draw back in one motion with no downward pressure. For the pics, I of course did not have to do the piercing.
 
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