How Do You Toothy Your Edge?

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allout

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After grinding or DMT Alignering the profile I strop/touch up with an 8” or 4” diamond stick. The 4” brass stick is very old and puts an edge that gives wicked bite on the thumbnail (saving my arm hair). Using the same setup on various blades the Mora stainless thus far has produced the most bite (by far), maybe because of the scandi grind. How does edge geometry play into the toothy edge? Does convex or flat profiles matter with the toothy edge? How do you test the sharpness of your toothy edges? I have been reading about the durability of a toothy edge in other posts and I have not made up my mind. I do like very much how well they cut. I chopped dead dry oak vigorously for 90 seconds with the Mora stainless and it still had the same bite, or so it seemed. I do like how quick and easy field sharpening a toothy edge is with a single diamond rod.

And, of course, How Do You Toothy Your Edge?
 
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Toothy is a realative term, some call a 300 grit edge toothy and others call a 2k edge toothy. Specific stones will impart toothy edges too, Japanese natural stones for example will leave a edge very toothy even at extreme finishes in the 10,000-20,000 grit range.

Geometry plays a role too, thinner blades are easier to obtain sharpness on regardless of grit. Thinner bevel angles help also, less metal to grind and thinner is always sharper.

To "toothy" a edge I like to start with a 1k waterstone then using a higher grit such as a 5k or 6k to lightly polish off the burr.
 
The only knife with a toothy edge I have is the CRKT Edgie. I got it years ago when I was working in retail and opened hundreds of cardboard boxes and plastic wrapped items a day. I hated those cheap disposable blade box cutters. The Edgie cut boxes and plastic like it was angry. It was pretty worthless for anything else. I much prefer a finer edge for anything else.
 
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I so prefer a toothy edge at around 320 grit over a edge at 600 grit. As it cuts a long time and is easy to bring back. DM
 
Jason B. said:
Toothy is a realative term, some call a 300 grit edge toothy and others call a 2k edge toothy. Specific stones will impart toothy edges too, Japanese natural stones for example will leave a edge very toothy even at extreme finishes in the 10,000-20,000 grit range.
Click to expand...

This^

Refined edges can perform like "toothy" edges as well. I find a better way to describe the sharpness at those levels is "stickiness" though. A good test to see how well a particular edge will cut fibrous material is paper towel or shop towel. On some junk knives I just stop at my 140 or 1200 atomas. Other times I go all the way to 160,000 grit.

Heres a video finishing up on the 140 Atoma
[video=youtube;j032eLxxhzc]https://www.youtube.com/watch?v=j032eLxxhzc&list=UURBNk3WxBpQFIrtqG-pnuzw[/video]

And illustrating "stickiness" at 160,000 grit
[video=youtube;6YSOwXBABP0]https://www.youtube.com/watch?v=6YSOwXBABP0&list=UURBNk3WxBpQFIrtqG-pnuzw&index=1[/video]

Japanese Naturals in particular show this "toothiness" as mentioned by Jason. Its one of their more unique properties. Even when getting up into the finer Jnats (Nakayama Asagi/Iromono , Hideriyama Tomae , Ozuku Asagi , Yaginoshima Asagi) they can display an interesting combination of "toothiness" and push cutting performance. And they are just plain fun to use :)

Heres Ken Schwartz demonstrating a an edge finished on Jnats , the knife is a clad Takeda.
[video=youtube;zEc_4Y9ws98]https://www.youtube.com/watch?v=zEc_4Y9ws98[/video]
 
All the above observations about toothy and fine. I also find the edge straight from a stone up to a medium, medium/fine stone and stropped on paper wind up very catchy - a lot does depend on the specific media being used for the grinding.

For woodwork I much prefer a finer edge, and reserve my toothy edges for EDU. My own anecdotal experience is that a finer edge lasts a lot longer (all else being equal) when working seasoned wood. The toothy one lasts longer for almost all other tasks.

Overall geometry maybe not a huge factor either way except that on broader edges - above mid 30s* inclusive, a toothy edge seems to work a lot longer than a fine one. I test mine with three finger sticky test and a draw/shear cut through hanging newspaper or paper towel.
 
I recently found that after putting a nice finished bevel on the blade, raise the spine up and create steeper but very small micro bevel to the edge, using the grey sharpening stone from Spyderco, VERY light if any pressure being applied and you end up with a nice toothy edge with a smooth bevel that will still push cut but will also provide good slicing action now too.

G2
 
For my Larger Blades I prefer a less toothy edge, more refined, but on a small knife, I like it to very aggressive, so I usually just free hand sharpen it on a DMT Coarse stone and use a butcher steel afterwards to straighten it out.
 
I use diamonds. I have tried ceramics and while the edge is sharp it doesn't cut the same. Even taking the edge all the way to DMT EEF I am getting an edge that can cut nice and aggressively while still having the keen edge. I don't think I can use anything else now that I have used diamonds extensively.
 
If I want a very toothy edge I go to my DMT coarse and strop on paper afterwards, it leaves a very toothy edge.
 
Bob, agreed. The coarse diamond leaves a good toothy edge. The edge left from a Norton India stone is similar only a little finer.
The two are close. I use these 2 edges most all the time. Still, it's a compromise. DM
 
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