What grit of abrasives do you use to sharpen?

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SteelDriver

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Jan 28, 2002
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I'm interested in hearing what grit of abrasive you guys use on knives for various applications (EDC, woodworking, choppers, etc.). Which grit for reprofiling and which for final sharpening? Is there a direct correlation between the edge angle and the grit you choose? I'd love to hear any additional insights you may have.

I've seen occasional posts in various threads on this topic, but I'm trying to consolidate things here. I'm going to pick up some wet/dry silicon carbide paper soon, but I haven't decided on which grits to buy. Thanks for your input.
 
This is all a matter of taste what one self prefer. Me for my self,i start always with a medium damond benchstone. Then i switch over to Arkansas stones. First a medium,then a fine i then finish with an ultra fine(black) Arkansas stone.

I use this sharpening order regardless in what i sharpen. I use this procduer on all my knives,regardless how big or small they are.The very last moment of the sharpening,is the one that gives the true razor edge,and that is the ultra fine Arkansas stone. I doesn´t tear of any metall at all,it´t just polish the knifes edge to the razor sharpness.

This is my personal advice,and everyone has their own habbits,but if you follow this stepps,and offcoarse has a high quality blade,you will end upp with a razor edge in the end. Happy trying,and watch your fingers!!

Manowar
 
I use all 4 of the DMT 2x6 hones

Black 220 grit
Blue 325
red 600
green 1200

I also use the Razor Edge fine hone. The razor edge fine hone gives me the hair popping sharp edge.

I only use the Black DMT to reprofile a blade for the first time.

If I don't have to reprofile a blade I use the blue or red dmt to get the wire edge and then I use the green dmt or the razor edge fine hone to get my finished edge.

The only way I can get a hair popping sharp edge is when I use the razor edge fine hone.
 
I always use the coarsest, fastest-cutting abrasive that I have handy for any kind of reprofiling or edge thinning. Life is short. You only generate more heat in the metal and sweat if you use too fine an abrasive. I learned this while grinding lathe bits. It was faster and created less heat if I used a coarser grinding wheel for shaping.

When you are working an edge you want a clean cutting sharp abrasive to minimize burr formation. A medium diamond hone or a 600 grit japanese water stone work well. Actually I use a belt sander most of the time. When I go down to the soup kitchen and sharpen 80 knives in 3 hours I use a 50 grit belt to rough down the edges. At home I seldom use below a 90 grit belt for rough work. If I don't have as much to remove or want to be a little neater I use 120 and 220 grit belts. I always use these after 50 or 90 grit belts.

After using the belts I neaten up and remove burrs with a 12" long 600 grit diamond bench hone. For most practical work I finish with the brown (medium-fine grit) rods on my Sharpmaker. If I want a smoother chopping/dicing edge I follow with the white rods on the Sharpmaker. If I want a bragging edge (rather than a practical edge) I may follow this with a razor strop. I have completely given up using Arkansas stones. They all cut slow and the ultra-fine ones leave an edge with little bite.
 
That's a cool chart Jeff, thanks for the link. I must admit that I've also given up on Arkansas stones. With the hard, carbide-heavy steels that I have to sharpen, they're just too slow. They still work well on carbon steel, though.

Good thoughts so far, keep em coming!
 
I'm with some of these other guys. I use the diamond stones; usually the DMT versions. I start with the coarse, then end up with the red(fine). Occasionally, I will go to the green(extra fine), but dont find that needed often. Actually, for most of my uses, the blue(coarse) gives me a really toothy, grabby edge. Sometimes, I stop there.
 
SteelDriver :

... what grit of abrasive you guys use on knives for various applications (EDC, woodworking, choppers, etc.).
Click to expand...

Jeff's answer was as usual very solid, go as coarse as you can on the shaping and finish with the grit best suited for the application, coarse for slicing, fine for push cutting.

In regards to angle, the teeth produced by a given grit get larger as the angle is reduced, thus a finer finish gives just as much bite. Also since the cutting ability has inherently increased due to the more acute edge, this further reduces the need for a coarse finish. In short, the more acute the angle on a blade, the less a need for a coarse edge for slicing.

For wood working, chopping and otherwise, a coarse edge makes no sense, you can't slice even soft woods, and microteeth on the edge just reduce push cutting ability and lowers edge durability and edge retention.

-Cliff
 
if you're going to be using the "paper over mouse pad" technique, you may want to start with 200-400 and go all the way up to 2000 - available at auto-body/paint shops.
 
The chart illustrates the speed of metal removal as a function of grit or abrasive size. Trivially, for a specific abrasive as you get finer the cutting speed slows down. The chart extends beyond that and compares different types of abrasives over a range of grits.

I would rather the caption read "Speed vs polish" through, as a very coarse edges can still be very sharp. But it is common to use the term sharpness to refer to extent of polish. It isn't uniformly defined very well some people simply use it to define cutting ability in general which then has it mixed it with geometry, blade balance etc. .

-Cliff
 
Buzzbait, Where the chart is indicating "sharper" it really means smoother. For example I find regular silicon carbide hones to leave a sort of ragged finish. The size of the grit is one factor, the shape of the grit is another, and the uniformity of the grit also comes into play. I get the feeling that silicon carbide hones have irregularly shaped and sized grit. In contrast japanese water stones (which are also silicon carbide based) have much more symmetric and uniformly sized grains. Diamond hones also have very uniformly sized grit and cut fast and even.
 
For EDC, I've become a zealous advocate of a dual-grit edge. When sharpening, I take the entire edge down to at least 600 grit, sometimes moving to a >1000-grit ultra-fine stone, and sometimes even a strop. This ensures the burr is long gone, and gives me a razor-polished edge that's great for push-cutting. Then, I put the knife back on a medium or coarse (250-350 grit) stone, and lightly take a few swipes in the back inch or two nearest the handle (where serrations would be if this were an actual partially-serrated blade).

I use the polished tip for opening mail, cutting thin-but-hard plastic, and any other type of push-cutting. I use the coarser back part for any kind of slicing. I get some of the advantages of a partially-serrated blade, but for things like food prep, I can use the entire blade because the edge is entirely in-line. Pick 5 random jobs, and my knife will overall outcut an identical knife that was sharpened to the same angle but left at all one grit.

For re-profiling, like Jeff Clark I use the coarsest abrasive I have, some examples being: x-coarse DMT hone, and very low grit abrasive paper. I've become a fan of abrasive paper in the past year, especially for re-profiling, just because it's so inexpensive, whereas an x-coarse DMT hone can cost anywhere between $40 to >$100 depending on your hone choice.

Joe
 
Originally posted by Cliff Stamp
I would rather the caption read "Speed vs polish"
Click to expand...
Thanks for the clarification, Cliff. This is something I've always suspected about this chart. Glad to know I was right.
 
Originally posted by Cliff Stamp
I would rather the caption read "Speed vs polish" through, as a very coarse edges can still be very sharp.
-Cliff
Click to expand...

Thanks. That makes a whole lot more sense. But does an extra-coarse diamond hone really bring a higher level of polish to a blade than "fine" (maybe 1200 grit) SIC wet/dry paper? Based on my experience, that's far off the mark. While 1200 grit wet/dry doesn't create what I'd call a highly polished edge, it's quite a bit more polished than the edge left by a Lansky extra-coarse diamond hone. Actually, I'd liken a 1200 grit SIC wet/dry finish to something closer to the fine grit finish of a diamond hone.
 
The SiC that the chart refers to are SiC solid hones, these are very coarse. SiC sandpaper however can get very fine, up to about twice as fine as an x-coarse diamond hone. The grit designations in general are pretty meaningless as they vary from one manufacturer to the other.

As for the chart in general, I believe it comes from Norton who sell abrasives, so its not exactly an unbiased source of info. However from what I have used, I don't see any strong contradictions with the exception of the cutting speed of the diamond hones. This assumes you use equally low force on all hones. If you lean on the SiC hones they will readily out cut the diamond hones many to one as you can only use them with light pressure as otherwise they will strip out.

-Cliff
 
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