Am I doing something wrong?

D

darinsbilliards

Joined
Nov 5, 2005
Messages
6
Ok guys, here is my question.

I have been freehand sharpening a long time, using a norton 220 waterstone and a spyderco ultra fine, as per juranitch in his book. This achieves an edge that shaves all the hair off in one pass, and no burrs that I can feel.

However, I purchased a norton 8000 grit water stone and after progressing to that, the edge feels like it has dulled, even though I have read the ultra fine is not as fine as 8000 grit. (And I am aware that ceramics are graded differently, but people on here have stated ultra fine to be ~4000 grit.)
If I then take it to a strop, it becomes somewhat sharper, but still doesn't take hair off like the ultra fine ceramic. My goal is to progress to cutting a free hanging hair, but I am not sure what the deal is. The only knife I have to practice on now is AUS-6A steel. I am thinking either that steel is difficult to hone that fine to pop hair (I know that steel isn't considered the greatest quality), or there is something wrong with my technique.

If I go back to the ultra fine, it readily shaves a lot of hair again, but won't cut free hanging. Any suggestions?
 
Maybe AUS-6A has too coarse of a grain structure to get the micro edge you want. It does seem weird that it gets duller on a finer stone, though. Maybe the different "stone" materials don't work well together as a sharpening system?

I would look into the "new wonder steels" like S30V and BG-42(sp?). Maybe they will polish down to that fine edge you want.

Here's a bit from another thread about sharpening angles that might be helpful too:

DGG said:
Will it hold an edge? Sure! That's a total angle of 30 degrees which is the way Spyderco factory ships most of their knives.

If you want to have some fun, sharpen the seconday/back bevel down to 6-8 degrees, and sharpen the primary/micro bevel to 10 degrees (20 total). You'll have a real hair splitter for sure.

VG-10 is good stuff and will hold an edge. It has radioactive cobalt in it (one of the few knive steels that use cobalt) so if you drop it in the dark it will glow and be easy to find. Here is some techy info about various knife steels.

http://www.ajh-knives.com/metals.html

Here's some sharpening info, geared towards the kitchen crowd, but has great pictures and explanations.

http://forums.egullet.com/index.php?showtopic=26036
Click to expand...

Not too sure about VG-10 blades glowing in the dark; is that true?!? If it is, that can't possibly be good for you, lol.
 
The VG10 glowing is a joke. AUS6 should take a NICE edge, if properly heat treated.
You make sure your angle doesn't deviate too high or you'll roll over the edge or you'll dull it. Does the stone need a breakin in?
 
GibsonFan said:
I would look into the "new wonder steels" like S30V ...
Click to expand...

S30V would worse most of the highly praised "wonder" steels are not optomized for fine edges at a high polish as they have far too much coarse chromium carbide. It is like trying to make fine molds out of concrete which has massive big chunks of rock in it. If the rocks are of similar size to the mold, then you can't form the mold.

darinsbilliards said:
If I then take it to a strop, it becomes somewhat sharper, but still doesn't take hair off like the ultra fine ceramic. My goal is to progress to cutting a free hanging hair ...
Click to expand...

How exactly are you using the waterstone? What is the sharpening angle? What do you mean by cut a freehanging hair? What kind of strop, how are you using it?

-Cliff
 
I never nit pick about the angles, I just try to keep it under 25 degress. I go more by feel than anything else. The strop came from knives plus, it is chap leather charged with green CrO. I raise it up on the strop a little, but at less of an angle than I used on the stone, so the edge won't round over. That's the way to do it from what I read.
 
I get exactly the same results you describe when using an 8000 grit Norton waterstone verses UF Sharpmaker rods. The 8000 grit does not typically do as smooth a job as the UF ceramic rods, I don't care what people say. Part of the issue is that the ceramic rods all start with a rather coarse grit base which is fused by heat into a finer finished structure. That structure is not all that similar to the conglomeration of unfused grit found in a waterstone. This isn't like comparing apples to oranges it is more like comparing apples to bananas.

To get your finest results out to the waterstone you need to use very light honing pressure and develope a slurry of finely pulverized hone grit. Norton waterstones are not as fine as Japanese waterstones. You might do better with something like a King brand 8,000 grit.

What works best for me is to go to a rock shop and buy some 50,000 grit diamond honing compound. It will come in a syringe or a watery spray. Apply that to something smooth like photo paper. Use that for stropping. That will put an extreme razor edge on AUS-6. Be sure to use very light stropping strokes. If you got a non-stainless blade of 1095, 52100, or A2 you could get a finer edge than with stainless. AUS-6 is good for a stainless. You could also try a blade made from Sandvick 12C27.
 
i use a splash of water, a little pressure easing up to almost no pressure, alternating strokes. for about a half dozen on each side.

Yes that's what has been driving me crazy. I read that norton's stones are actually more coarse than other japanese, so I have been looking at the kitayama 8000. It just seems the ultra fine bench stone puts a great edge on there, but you know I am obsessed with seeing how far I can take it. I don't want to buy any more stones unless they actually do put a finer edge on than with the spyderco stone. Because after buying the norton I was a little disappointed. I have had it for almost a year and tried all kinds of variations with pressure, angle, etc. and always get the same result.
 
On the 8,000, have you tried pulling the blade back away from the edge, like stropping?
 
I can see that you are going to get really obsessive about this sharpening thing, a man after my own heart. You need to know the truth about fancy hair cutting tricks.

Secret #1 is that not all hair is created equal. There is thick hair, thin hair, curly hair, straight hair, hard-dry hair and moist-soft hair. If your hair is thin, hard-dry, and straight it will be much harder to cut free hanging than thick curly damp hair. You may already be getting your edge sharper than others that you try and compare yourself against.

That doesn't mean that you shouldn't improve your pointless hair cutting edge technique. Secret #2 is that while you don't need a precise angle control for a hair cutting edge you do need a very low angle. For that kind of work you want to hone somewhere between 5 and 10 degrees PER SIDE for a total included angle down in the 10 to 20 degree range. That will leave you with a very weak edge if you are sharpening an AUS-6 blade that is only about 56 RC hardness. You can do that with AUS-6 for light-duty work and a bragging hair-cutting edge, but you should really use a harder alloy (which is also very fine grained). A good choice would be 1095, 52100, or A-2 at about 62 RC or harder.

As I said before the best way to force a stainless edge to extreme sharpness is to strop it with ultra fine (submicron) grit diamond abrasive. First you should sharpen the edge via normal methods as sharp as possible to get a flat and very accute edge bevel (stopping tends to round off your edge if you do it too long on too soft a strop or apply too much pressure while stropping). Then strop on a relatively stiff strop coated with submicron diamond grit. This gets a sharp edge on stainless as measured by the toilet paper cutting test.

You can get a kit with a variety of diamond grits from Woodcraft stores. It even includes a small diamond hone.
http://www.woodcraft.com/family.aspx?familyid=4666

You can get individual grits through Graves (you want around 50,000 grit):
http://www.gravescompany.com/polishin.htm
 
There are really fine stones, Shapton for example, but they are expensive. Buffing compounds like Jeff mention on *flat* surfaces are much cheaper. Jeff made excellent points as usual noting that is a very high angle to try to obtain a high cutting ability, even if you get the blades very sharp they still may not cut well and there is a lot of variation in human hair.

In regards to method, angle of the blade on the hone is important. You want the grit scratches to gross each other for maximum refinement and burr minimization. The pressure is also key, going very light can actually not be the best idea because you can lose cutting action as it does take a certain amount of pressure to cut well, even with diamond.

Jeff Clark said:
I get exactly the same results you describe when using an 8000 grit Norton waterstone verses UF Sharpmaker rods.
Click to expand...

For all steels of just stainless?

-Cliff
 
It's hard to remember now if I used my 8000 grit Norton on anything but stainless. I have about 100x more stainless blades to play with than carbon and I may not have tried it on any carbon steel. What I have is a combination 4000/8000 stone that feels more like a 600/2000. I took it to my office so I can sharpen friends' knives when they ask. I also have a cheap Idahone ceramic V-sharpener for edge finishing.
 
I appreciate all you guys responses. I will definately look into the 50,000 diamond spray. Do you guys usually follow Juranitch's reccomendation of using only a very coarse hone to grind in relief, then follow with the finest possible for the edge itself? Or do you guys progress through finer grits, raising burrs and honing them away until you are at your finishing stone?

In my experience, using a very coarse hone (like 200 for example) and then proceeding to a finishing hone does provide a great edge, but it feels like it has a harder time cutting through material because of the steel's roughness from the coarse stone. Polishing the whole bevel seems to really lower the resistance, or maybe I am biased and I just like mirror polished bevels!
 
I do most of my honing work with a coarse hone, but I do advance through a series of finer grits pretty rapidly to smooth out the bevel. I cheat and do most of my heavy work on a belt sander. Depending on how much material I need to remove I start with 60 to 120 grit. I usually advance to 600 grit before I switch to manual hones. Usually I step up to 1000 grit Shapton Professional waterstone and then over to a Sharpmaker. I tilt the Sharpmaker back and forth so that I can hone at 10 degrees per side. I finish by stropping on photo paper with diamond grit. I support the photo paper on a pad of paper.

Most of the time and the heavy work is done at the coarsest grit on the belt sander.
 
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