More Questions on Sharpening`

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me2

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Oct 11, 2003
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There have been a few threads on this lately, so I figured I'd combine some of my questions not discussed in the others.
First, how fast do water stones cut? I was thinking of angling for a 1000/4000 grit combo stone for fathers day. The Complete Book of Sharpening says that an 800x man made stone will cut faster and leave a finer finish than a 90x Aluminum Oxide oil stone (Norton Course India?) If this is true, I'd definately like to try it. For angle control, I usually use a miter cut block screwed to a base. Can I store a water stone in water, then take it out for use, wetting it occasionally, or does it have to sit in water?
Second, does anyone sharpen knives on unsupported wet/dry sandpaper? I cut a piece of 220 grit 11x9 inch paper into 11x1 inch strips, and just put an edge on my AFCK that will cut hair, although it has to be a slicing motion. Just took 11 strokes per side, and about 3 strokes per side on my strop. I got the idea from Cliff's post about using slack sanding belts hooked on doors for reprofiling.
Thanks for all the info.
 
oh..oh..oh...I get to post before Cliff does....:D :eek: :D




what was I going to say....? :confused:



:p
 
can't help ya with the waterstones, but I've done my fair share of sharpening with sandpaper. You're creating a slight convex edge if you don't use a hard backing (glass, stone, etc.) - and that can be a very good thing (as long as it fits your particular needs). ;)

Different grit papers will give you different types of edges. Obviously, the higher you go, the more you polish and the better it will push-cut. You can still get a shaving edge at 220 grit, and have enough coarseness to draw-cut well.
 
That was what I was aiming for, and it was so fast. The bevels arent perfectly even, since I did it free hand, but I dont think they were even to start with. The AFCK had an unfortunate run in with a 320x belt on a belt sander.
 
me2 said:
The Complete Book of Sharpening says that an 800x man made stone will cut faster and leave a finer finish than a 90x Aluminum Oxide oil stone (Norton Course India?)
Click to expand...


India stones clog up badly because of the bonding media which heavily masks the abrasive. I use a 100 grit AO sanding belt on a piece of hardwood for profiling, beats even my 200 SiC waterstone many times over.



Can I store a water stone in water, then take it out for use, wetting it occasionally, or does it have to sit in water?
Click to expand...


It is easier if you just let them soak, as it takes time for them to fill up when dry, especially the finer ones. Just store them in any old plastic tub.

-Cliff
 
Cliff, thats kinda what I meant. Just store them in a container of water until needed, then take them out and put them on my stone rest, then put them back when finished.
 
That's all I do, I just store a bunch of small ones in an old yogurt container. I rinse them off when I take them out to prevent contamination from other grits. If you want to be really careful you would keep them in idividual containers. Which I would do if I have high grade Japanese waterstones.

-Cliff
 
im very new to knife sharpening and recently purchanced a "King waterstone ice bear" 250 and 1000 grit combo made in japan 19.99 at a woodstore.

now i have a bunch of crappy knives ranging from a stainless cheap dragon tanto to a mystery stainless pakistan throwing/boot knife.

now i can get these both push paper sharp but for the life of me they wont cut my armhair!

i make sure to keep a constant angle around 25 degrees to form a bur then flip over to remove burr and then stroping with a old white "wood is good co." material thingy using aluminum oxide.

they cut paper perfectly but are my armhairs like supermans??? they just wont cut :grumpy:

please help me refine my technique. i have read the sharpening FAQ and several others online but i want armhair popping sharp, not just pushpaper sharp

thank you in advance
 
Drakoon,
1000 grit may be too course to push cut arm hair. You may also be rounding the edge on the strop. Stropping is a little tricky. I do mine with an 11" piece of leather 1 " wide with white buffing compound clamped to the edge of a table. You have to be careful to lift the edge straight off the strop, and not roll the spine up as you come off the strop. That will round the edge. I sharpend my AFCK on 220 grit sandpaper and was able to cut hair, but not push cut. I had to use a slicing motion. I'm not recommending that you slice into your arm hair, and possibly your arm, but with the 1000 grit finish before stropping, your edge may be a little toothy for push shaving hair. Also, you may want to lower the angle you sharpen with. If you form a burr at 25 degrees, do you increase it to remove the burr? If so, you may want to form a burr at 20 then remove at 25 or even less. Most of my knives have a 17 degree bevel, with a final edge put on at 20 degrees on the Spyderco Sharpmaker. This allows for quick sharpening for a while before the bevel has to be ground back to 17 degrees.
 
Drakoon, You are confused about removing burrs and about honing angle. Honing one side of the blade at a time will always leave you with a burr. The burr is very flexible like aluminum foil projecting out from your edge. When you work one side you will form a burr. When you switch sides you will remove some of the burr, but you will simply fold a lot of the burr to the other side after the switch. If you keep honing on the second side eventually you will just form a burr that is now on the other side of the blade. To remove the burr you need to do some edge-forwards honing while alternating left-right-left-right sides. When you are almost done your primary deburring step will be to tilt the blade up to around 45 degrees for a few light edge-forwards strokes alternating sides. This will cut the burr. Then finish at a lower angle.

The other thing you need to know is that you want to do your heavy blade thinning honing at a lot lower than 25 degrees per side if you want a shaving edge. I would go for more like 12 to 15 degrees per side and then finish with a very small number of strokes at 20 degrees per side (like maybe 5 strokes per side). You want to use a fine stone for those strokes.
 
Thanks for the responses!

hmm it seems i have much to learn but practice makes perfect right?

i should of clarified, i use the 250 grit side of the stone after using the 1000 grit.

the 250 side is almost smooth

hmm i guess i was cutting paper by slicing and not push cutting. but after slicing the edges from the cuts are perfectly smooth, thats good right?

:D i cant wait to try both of your great tips out tomorrow hehehe

thanks again guys
 
The 1000 grit is finer than the 250, in grits the higher the number the finer the stone. In regards to sharpness, shaving ability is much higher than slicing paper, about 2-3 times as sharp (depends on the paper and the type of hair). The problem is most likely one which Jeff noted about small amounts of burred edge remaining.

-Cliff
 
Cliff Stamp said:
It is easier if you just let them soak, as it takes time for them to fill up when dry, especially the finer ones. Just store them in any old plastic tub.

-Cliff
Click to expand...

Cliff, if I recall on another thread I recently started, it was suggested that the finer japanese waterstones (6000-8000 grit) should in fact NOT be stored in water permanently. I have the 800 and 1200 stored in water. Should I do the same with the 8000-grit one? What is the best way to do this?

Thanks,
George
 
HoB, brought up an important point in the last thread :

http://www.bladeforums.com/forums/showthread.php?t=299467

Which is that since the very fine stones like the 8000 absorb water very slightly due to the very dense bond you don't need to keep them in water.

However I have let mine (4000) dry out competely and it takes too long for it to get wet enough to function well so I keep it stored in water always.

The 8000 is a very fine stone, I would make sure to keep it separated from the others, and rinse off the blade well before switching grits to make sure you don't get cross contamination.

-Cliff
 
So, would you store the 8000 in water permanently, assuming it's in a separate container?
Sorry to keep dwelling on this, but I would like to get to the bottom of it from people that know what's going on!!

Thanks again,

George
 
ahh thanks cliff for setting me straight with grits

if i have a 250 and a 1000, whats the next step towards razor sharp? 1500? 2000? 8000 :eek:

im a poor student so i cant go out and buy 8 more stones to get from 1000-8000 so what are the go betweens?
 
I would try it not stored and see how long it takes it when dry to absorb enough water to be productive, if this was too long I would store it wet.

In regards to stones, you can just jump from 1000 -> 8000, all this means is that it will take longer to polish. The more stones you have inbetween the faster it goes.

You can also experiment with sandpaper, you can buy it for cents a sheet and it gets up finer than the 8000 stone. This way you can figure out which grit you like to finish with, without spending all the money to buy the stone.

You may find for example that five micron is enough of a polish for you, or you might want to got down to one. It depends on how you use the knife, so you need to experiement with various finishes and see.

-Cliff
 
ah thanks for the sandpaper tip, im using my cheapo knives right now really just for sharpening practice before i buy any good knives.

with sandpaper i attach it securly to a mousepad and it conforms to the blade angle? is that all there is? do i strop or edge forward sharpen?
 
Often it is difficult to hone edge-forwards on paper over a mousepad backing. The edge will tend to snag and cut into the paper. I use a hard backing and wide paper while I thin the edge down. For the finishing step I strop (edge trailing) with very light pressure with a soft backing. The softer your backing the lighter you need to stroke, otherwise the paper wraps around your edge and may make it too obtuse.
 
I have used waterstones for many years to sharpien my wood working tools. The store in water or store dry all depends upon the manufactureres recommendation, the bonding agent used will determine how to store.

The best man made water stones today are made by Shapton in Japan, they recommend not to store in water, just apply liberal water to the surface. The bonding used will break down in long term water storrage and weaken the stone.

Norton also makes good quality water stones,,,from the Norton web site: "Prior to use, stones should be immersed in water for 10 minutes and kept wet during sharpening. EXCEPTION: 8000 grit polishing stone needs only a splash of water on the surface to cut properly." They do not recommend permanent storrage in water.

There is no simple answer to the store wet or dry question. "It all depends"

Why water stones??? They have a weak bonding adhesive and the grit material constantly breaks away exposing new abrasive grit. Very quick and efficient especially on tough alloy steels, we use A2 Cryo treated very widely for plane blades. The water stones are much faster than oil stones or ceramics. Disadvantage is the quick wearing properties will require flattening much more often than oil or ceramic stones.

Sandpaper on glass or other flat surfaces is O'K for knives however, the plane blades do not sharpen up very well due to dubbing or rounding of the edge with this system. The grit breaks away from the backing so fast that the edges of the plane blade are abraded more than the center and rounding is very hard to avoid.

Regards,
FK
 
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