Polished? Coarse?

D

db

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Oct 3, 1998
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Or someplace in between? For your every day carry knife what type of edge works best for you? I’ve gone from preferring coarse to very polished and back to coarse. I now have really settled on something in between, an 800 ish to 1200 grit finish. Example since grit size varies so much is a Spyderco med bench hone, a Norton 4000 water stone, or a hard Arkansas. I find I still get a pretty good push cut and pretty good slice with these. For my edc that could be used on anything it works good for me.
 
I am also looking for the answer to this question for myself. As my sharpening skills become more honed (get it? ha), I think I'll be able to judge this better. As ludicrous and unexamined as it sounds, the test that I've used for a long time is my fingertips--I kind of lightly slide the end of my finger (by the fingernail) along the edge (like slicing a layer of skin off, not blade pointed into flesh) and notice how easily it slices and bites into the skin. I don't go deep, of course. It kind of gives my hands that work-weathered look :) . I think the finish that has provided the most gratifying results in my personal test are in the 1200-grit neighborhood.
 
I don't know where it falls in relation to to sandpaper grits, but I do almost all of my sharpening with a red DMT stone. . . I belief that it is "fine" by their scale. It gets most of my knives shaving sharp pretty easily, but not to that "hair popping" state that I've heard everyone talk about here. That's plenty sharp for what I do with my knives. I've also taken to touching up my knives by stropping them on cardboard. I work in a warehouse so it's easy to just periodically give my blade a few swipes on the boxes that I'm opening and cutting up anyway. It seems to keep them going a bit longer before I have to take them back to the stone that way.
 
Don't know about you guys but I myself have found stopping with Edgepro 250, 300 stone purfect for everyday use.
I do more slicing with my blade than push cutting. I do admitt though being able to dazzle your friends with how sharp your blade is was always a favorite of mine.

armilite
 
Lewdog
That test for sharpness isn’t ludicrous at all. In fact it is very close to a well known Makers sharpness test, Murray Carter’s 3 finger test. He pretty much does the same thing but with 3 fingers not just one.

Salamander
That is pretty much the same finish I use. Yes I’ve also found maintaining an edge will keep it sharp a long time, and stropping on cardboard works great.
Armilite
I’ve never used an EP, so am not sure how coarse that really is. Sounds pretty coarse but for mostly slicing I’d choose coarse too. Truthfully even my very coarse finished edges are a lot sharper than most non knife nuts have ever used.
 
Salamander42 said:
I don't know where it falls in relation to to sandpaper grits, but I do almost all of my sharpening with a red DMT stone. . . I belief that it is "fine" by their scale. It gets most of my knives shaving sharp pretty easily, but not to that "hair popping" state that I've heard everyone talk about here. That's plenty sharp for what I do with my knives. I've also taken to touching up my knives by stropping them on cardboard. I work in a warehouse so it's easy to just periodically give my blade a few swipes on the boxes that I'm opening and cutting up anyway. It seems to keep them going a bit longer before I have to take them back to the stone that way.
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I also use DMT stones. I've found the Extra-fine (green, 1200 grit) works great for daily maintinance. I just do a few strokes after work each day, and on my soft gerber paraframe or my nice Imperial barlow, thats all it takes to work out any imperfections found. Leaves a nice micro-serrated edge too. With something like a 9 micron finish, its definately not a coarse edge, but still remains toothy thanks to the diamonds cutting and not burnishing at all.
 
Buck268 said:
With something like a 9 micron finish, its definately not a coarse edge, but still remains toothy thanks to the diamonds cutting and not burnishing at all.
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Note the level of "coarseness" depends heavily on the edge angle. Specifically it is proportional, so a grit at 10 degrees is twice as coarse as the same grit used at 20 degrees. If you sharpen really low like 5 degrees, then even what people would call medium-fine is REALLY coarse.

-Cliff
 
Cliff, can you describe how there is a relationship between grit and edge angle? I don't understand. Maybe what I think "coarseness" means is not what you think it means. I think of it in terms as the "teeth" aka micro serrations left on the edge by the grit. I don't understand how the angle of sharpening will change the height of the teeth at the edge.
 
As the steel gets thinner, the teeth will be larger at a given finish. You can see it really dramatically on something like an Opinel if you sharpen flat to a stone at the primary angle as the angle will be about 3 degrees or so.

-Cliff
 
I mainly sharpen with a mousemat, and my preferred method is to take the edge to 2,000 grit sandpaper then rough up the last centimetre or so of the blade (the part nearest the handle) with 400 grit - as outlined above. I find this the best all-round result, because I can still slice ripe tomatoes, starting at the furthest point of the blade.

However, I do quite a bit of food preparation - if that isn't too grand a term for making my own sandwiches every day.
 
Spyderco ultrafine and chromium oxide loaded strop on one-handed folders (zdp-189, 13C26, M2, 8Cr13MoV), red dmt on plain edge blade of Leatherman Wave, touch up the serrated blade with Spyderco Profiles.
 
When just using a bench stone, I try and stay at dmt red. For smaller knives, I'll keep going to green, and then either a loaded strop or a spyderco fine ceramic. Don't know why, I just like more polish on my pocketknives.

When I'm using my edgepro, it's all the way to the tapes, I just can't stop myself! :D
 
With my smaller knives, I tend to go very high polish because the bevels are so acute they don't need to be left coarse. On the really large knives I have them polished because they are choppers. Right now I only tend to leave coarse bevels on the medium sized utility knives and I leave them really rough, like x-coarse DMT. They will all shave, push cut paper, etc., and are very aggressive on a slice.

-Cliff
 
Hi Cliff,

Cliff Stamp said:
With my smaller knives, I tend to go very high polish because the bevels are so acute they don't need to be left coarse. On the really large knives I have them polished because they are choppers. Right now I only tend to leave coarse bevels on the medium sized utility knives and I leave them really rough, like x-coarse DMT. They will all shave, push cut paper, etc., and are very aggressive on a slice.
-Cliff
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How do yiou get rid of the burr that such coarse stones give, even if only push honing? And what angles are you edges honed to? Do you set a micro bevel?

Best Reagards
Frank
 
I minimize the burr through proper honing techniques. If you are producing large burrs then there are a few things that need to be adjusted. It will be a combination of a number of factors:

-Too much pressure on the stones
-Clogged or worn stones
-Weakened steel in the edge
-Overhoning on one side past the burr formation

Currently I can hone even steels like AUS-4A to a crisp edge with a x-coarse DMT with minimal burr formation, nothing seen under 10X mag, push cut newsprint and cut a lot of cardboard and still shave, details in the reviews.

For a novice I would recommend the following technique :

1) Sharpen on one side until burr
2) Flip and repeat
3) Cut right into the edge with a u-fine stone to remove burr
4) Alternate sides until sharp

Microbevel if necessary. My microbevels are not usually distinct, maybe 1-2 degrees above, unless the knife is for high toughness like a chopper. Then the edge will have a primary of 6-8 and a secondary of 11-13. This assumes high end steel, for soft machetes this has to be increased a few degrees, 8-12 and then 14-18.

On all knives that just cut things, the final edge angle is almost always <10 degrees for the knives I personally use unless it isn't a knife so much as some kind of utility tool.

-Cliff
 
Most of the knives I use are really high end, the steel is completely optomized for the task of the knife. None of the sillyness like high carbide stainless in a chopper. This, and a lot of experience using knives, lets me reduce angles to their barest minimum so as to produce maximal cutting ability. There are about half a dozen guys here with similar edge geometries. Some of my primary blades are actually 4-6 degrees in the final edge angle. They are also not nearly as restricted as people think. When my knives go over ten degrees they are more for cutting metals and very rough work like on bones and such.

-Cliff
 
with 4 degree angles do you have problems with them dulling faster on certain materials?
Is dulling less of an issue to you?
 
The knives I typically use are designed with that use in mind so they are 1095 at 66 HRC, M2 at 65 HRC, etc. . They are made to take and hold very fine angles. The cutting lifetime is also extreme due to the very fine geometry. With the cutting force much reduced, the rate of blunting is also because there is much more control in the cutting. Edge holding is important to me which is why I pick the steels and the heat treatments accordingly. The same steel can have excellent edge retention in one knife and poor in another because it suits one class of work and not another. This is a point that many users and makers miss completely because you will see things like XXX has good edge holding. This is in fact impossible to say. It is just as meaningless as saying 0.0625" is a good thickness for a knife. That kind of depends on how the knife is going to be used obviously.

-Cliff
 
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