yet another sharpening post

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Nov 4, 2004
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i've read all manner of posts on this. some say to move the knife in circles across the stone, others say to use a sweeping or cutting motion, and others say to use a straight push. are the different techniques used to get different effects, or is it just a matter of taste?

thanks for the help
 
justine120 said:
i've read all manner of posts on this. some say to move the knife in circles across the stone, others say to use a sweeping or cutting motion, and others say to use a straight push. are the different techniques used to get different effects, or is it just a matter of taste?

Circular motions are for removing more steel faster like while reprofiling. There is a high likelyhood that you will scratch your blade while doing this :( . Pushing,"slicing" is for edge refinment after the edge has been formed.
 
It is purely a matter of preference. The advantage of the circular motion is that it helps even out the amount of grinding along the length of the blade. It is my preferred method. Do whatever works best for you.
 
I do a combination circular, x figure 8 etc. motion on the coarse stone (just something I picked up from my brother's machinists handbook where it was talking about moving the work piece in a figure 8 motion when flat-lapping... this evens out the directional forces so that you grind evenly over the whole surface... otherwise the pressure tends to concentrate on one side and you wind up curved rather than flat).

On the middle and fine stones I tend to do it like in the Shapton video on woodcraft http://www.woodcraft.com/family.aspx?DeptID=4026&FamilyID=5162 or in one of the susin videos on this page http://www.suisin.co.jp/Japanese/tokusyu/2004-12/index.htm (sorry, it's in Japanese, but basically, fingers on the back of the bevel, knife on a slight diagonal and back and forth walking along the length of the blade, and removing the burr between stones). Final touches I basically do the same but with very light pressure or do only an edge-trailing stroke on alternating sides as if stropping on the stone.
 
I really find it easier to keep an angle when using a slicing or stropping motion opposed to a circular one. But raising a good burr is a problem when using a pushing (slicing) motion, with which I find I can keep the mos constant angle. The best results I've got when stropping with a firm two hand grip way from myself, holding the knife in a straight angle to the abrasive. This was with a soft surface (for a convex endge) though, which is more forgiving.
 
You'll hear some tell you that the circle or swirl pattern sharpening method is the worst thing you can do and they'll even say why in great detail at times but the truth is there is no right or wrong way to sharpen if it meets the same end result: that being a sharp ass knife edge.

I know a professional carver that does things free handed with a knife that would blow most people away. He is so talented it blows me away with the stuff he can do with a block of wood. He sits and sharpens his knife with a little swirl pattern and then strops and goes back to work and I've watched him do this countless times. You couldn't tell this guy it doesn't work because he will prove you wrong when he starts carving big slices of teak all over the floor with one of his knives.

If pushing the blade from the tip to the back on a stone or strop is what works do what works. If slicing into the stone is your cup of tea do that. The end result is really all that matters. There are as many sharpening methods out there as there are stars so, the real trick is finding the one that works for you IMO and getting proficient at it. Just remember that frequent light sharpening (maintaining) is much easier than infrequent radical sharpening and go from there.
 
I think that circular and figure-8 motions originate from techniques optimized for oil stones and water stones. When you work with these stones the liquid breaks down some of the surface of the stone and gives you some extra abrasive action. When I was young (say 45 years ago) almost everyone used oil on their whetstone. In my Cub Scout handbook it said to use oil and a circular motion on one side of my blade and then the other. That is how I first learned to do it. If you read the directions on a classic Japanese water stone it directs you to use a figure-8 stroke to build up a slurry as you work.

These techniques work pretty well for rough sharpening a blade, but you don't have to be that fancy. If I have a lot of material to hog off a blade using a bench stone I just use a back-and-forth stroke that abrades as I go forwards and backwards. Even with an oil or water stone you get a lot of slurry that way and it takes off material.

The thing that I noticed back 45 years ago was that working one side and then the other tended to leave some loose metal along the edge, something like aluminum foil. I decided that I needed to do something to make the edge more even and get rid of what we now call a "burr" or a "wire edge". I'd seen the barbers stropping razors in the movies so I started using a stropping stroke on the hone as a finishing step to my sharpening. This left me with a shaving edge, but it didn't seem to last very long.

I read more on the topic and found this other advise. This was to use edge-forwards strokes alternating sides. This didn't seem to leave me quite as sharp an edge as my edge-trailing stropping strokes, but the edge seemed stronger. I developed the opinion that this method did a better job of cutting off the edge burr while the stropping stroke was partially removing the burr and partially just lining it up with the edge. I settled on using edge-forwards honing strokes followed by stropping on leather impregnated with jeweler's rouge.

These days I rough down a blade one side at a time using any old stroke then move on to edge-forwards. I often finish using a Spyderco Sharpmaker ceramic V-rod system which is designed to be used with edge-forwards strokes. Depending on the alloy I may also do some stropping on leather afterwards.

If the edge-forwards strokes don't automatically get rid of the burr as I work I do a few very light edge-forwards strokes at about 45-degrees to cut it off. I do this a little before I finish my honing.
 
I generally shave off the burr between stones (or even sides if it is easy to feel... some of the stainless steels seem to be the worst at forming big floppy tenatious burrs that don't want to come off)... sometimes by slicing into a block of wood at an angle... this tears it off and isn't as elegant as my second method. But, getting rid of it seems to help as a burr can tend to prevent the bevel from laying flat on the stone and keep you from getting a precise angle on the other side. Getting rid of it asap also keeps it from coming off in chunks on the stone where it can form little balls in the slurry and get under the blade causing it to chatter on the stone (or give you those darn metal slivers in your fingers.)

The other method I use is to take it off on a finer stone... say if I've honed one side on the 2k stone and have a noticable burr on the other side, I'll put the burr side down on a 5k or 8k stone at just a fraction of a degree higher angle, put my fingers on the back (keeping the pressure even by walking them down the blade) and slide the blade off the stone sideways... along the edge lengthwise (like in those pirate movies where you see them sharpening their cutlasses with a hunk of rock by running it up and down along the length of the edge)... this leaves a little black line on the fine stone that used to be the burr. Then go back to the 2k stone to hone the other side (then remove that burr and go to the next finer stone).

The burr is nice to tell if you've sharpened to the edge, but otherwise it is a pain so I get rid of it before sharpening the other side. Some of the carbon / tool steels are nice in this respect as they form tiny insignificant burrs that come off as fine dust in the slurry, so I don't bother to remove them like I do the foil that forms on the edge of BG-42 etc.
 
STR said:
You'll hear some tell you that the circle or swirl pattern sharpening method is the worst thing you can do ...
No there are far worse things, that just generates a completely random tooth pattern along the edge which leads to quick blunting unless the polish is raised so high the teeth are polished away, in which case it doesn't matter how you apply the finish, outside of burr formation..

You couldn't tell this guy it doesn't work because he will prove you wrong when he starts carving big slices of teak all over the floor with one of his knives.
This is more geometry not sharpness, sharpness would be cutting very thin slices. If he is working with older knives it is also not overly sensible to compare to newer steels which can be problematic to sharpen with similar methods. I can sharpen a old carbon steel kitchen knife easily in a way that would destroy the edge on a 62 HRC D2 blade.

-Cliff
 
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