Thoughts on smooth vs coarser (toothy) edge

[jackknifeh]

From all of my somewhat accurate and unscientific and not very controlled testing as well as every day carry and use of the knives I use in the kitchen, in my tool box or in my pocket here are my thoughts. I'm sure many will find them somewhat useless. But here they are anyway. :)

I haven't been able to tell any diffrence in any of the cutting I do being better or worse depending on if I have a smooth or a toothy edge. I would call an edg toothy if I finished with a 2k grit or under. Abov 2k I start considering the edge smooth. I've cut up cardboard mostly as a test and while I can feel a difference when I'm paying attention I can't say one cuts better than the other. I think I prefer a smooth edge but I won't swear by that. A smooth edge glides through about anything like butter. A toothy edge may rip through rope or cardboard better but I can't swear by that. If I can't tell a real diffrence with basic cutting and no lab equipment it doesn't matter to me. So, I like smooth edges better but that may change tomorrow (or this afternoon :) ). Blade thickness and edge angle plays a much bigger role regarding cutting performance IMO.

So, why would I go to the extra effort of putting a smooth edge on my knives? One benifit, and this is minor, is when I perform touch ups and can do it with a 4k or 8k or Spyderco UF grit stone I will be removing less steel per touch up. That's all. But, when you have a bug for sharpening even when it's not really needed or you just want to keep your edges tip top all the time, touch ups with the Spyderco UF stone is quick and easy. Of course if the edge has gotten dull enough that the UF stone would take a long time, start with the next coarser grit up in whatever stones you have. But quick touch ups with the finest grit possible to accomplish the job might make a diffrence in steel removal over the years. I think about this because of the amount of sharpening I've done in the past couple of years. I've removed enough steel from some of my favorite knives to be able to tell a difference when laying one beside a new one. I've sharpened almost an eighth of an inch off the length of my D'fly.

There could also be an argument to touch up using strops becaus they probably remove less steel than even the finest grit stones. But, with enough practice you will get the edges hair whittling using only stones. If you refine the edges even more with strops and very fine grit diamond sprays or whatever you could then whittle the whittles of your hairs. :)

My thoughts, useful to anyone or not. :)

Jack

[bh49]

On my pocket knives I am leaving toothy edge (medium sharpmaker Rods, about 600 grit). At this point the blade can shave. With kitchen knives, wich mostly do push-cuts I go a little higher with fine (~1200) or UF (~2000) rods.

[Evil D]

Anymore it just depends on my mood and if I'm in the mood to spend the extra time polishing a bevel. I like the looks but do somewhat prefer a toothy edge for EDC. A toothy edge will slice anything, but a polished edge will have problems biting on some things and will just slice on the surface. I don't really know many real world uses for push cutting. Most if not all of my typical everyday cuts are draw/slice style cuts. I think a toothy edge is more versatile than a polished edge and some say a toothy edge lasts longer.

[Stuart Ackerman]

Toothy works for most of my daily applications...

[xceptnl]

I find the edge finish only important when comparing the workable sharpness levels of the same steel. I find that a more polished edge doesn't really reduce the long term sharpness of VG-10 when compared to a more toothy (less than 1K) edge. This means when I sharpen my VG-10 knives I should be using the Fine or Ultra-Fine stone and more work to minimize the amount of steel being removed. Other steels like XHP and D2 I notice a difference in how long the toothy edge lasts vs. a polished one. This doesn't mean I won't polish the bevel and put on a toothy micro. I like the long term edge retention, but not at the sacrifice of how blingy the edge looks. What else would I do to impress my friends? :D

[VashHash]

It depends on the steel for me. CPM always get the coarser edge. The larger carbides work better with it. Finer grain steels (ZDP, M390, K390) usually get finer edges and hold them better in my experience. I make sure my straight razor is mirror polished before each shave thats for sure. I just find better utility in coarse edges. I of course try to keep my serrated edges as polished as possible. VG-10 i find works fine either way same with 154CM. I used to shave with my ZDP and likewise kept it very polished. Different strokes for different steels.

[xceptnl]

Different strokes for different steels.

well said... pun intended?

[GaTChE]

To the OP: it seems that different folk define the cutoff between toothy and polished differently. Perhaps you'd notice a difference if you compared a 325-600 grit edge to your 2k and up edges.

[VashHash]

Pun always intended. My main Sharpening tool is a blue dmt pocket stone. Carry it pretty much daily and use it on almost all of my knives. Except my polished zdp of course. I find the coarse edge more versatile. But there is a secret to cutting rope with a really polished edge. Cut diagonally and just push. Don't pull cut. / ancient ninja cutting technique passed down from generation to generation at the local malls.

[jackknifeh]

To the OP: it seems that different folk define the cutoff between toothy and polished differently. Perhaps you'd notice a difference if you compared a 325-600 grit edge to your 2k and up edges.

I can tell a difference between a 500 grit toothy edge and one finished with 4k or higher when I'm "testing" the difference. Then I'm actually thinking about it. Then if I decide to leave a toothy edge on an EDC knife I don't need to think about it every time I cut something like you do when "testing". You just assume you have the edge you want and cut. :) But if it's toothy or smooth I still never get the feeling that I shoule have "the other" type edge when I'm just out there in the world cutting everything I see. :) I think I'm expecting one to be 10 times better than the other when the reality is that both work and for EDC knives the differences may not show up as noticable. Now if you cut rope all day or cardboard or something then one or the other would really be more benificial I supposee.

Pun always intended. My main Sharpening tool is a blue dmt pocket stone. Carry it pretty much daily and use it on almost all of my knives. Except my polished zdp of course. I find the coarse edge more versatile. But there is a secret to cutting rope with a really polished edge. Cut diagonally and just push. Don't pull cut. / ancient ninja cutting technique passed down from generation to generation at the local malls.

I'll remember that for cutting rope with a polished edge. Who am I to argue with established techniques of mall ninja's. :)

Jack

[Officer Gigglez]

Toothy works for me.

[glbpro]

I had an experience with this issue recently with my Salt 1 - this is probably the closest thing to a beater Spyderco that I own, and I'm not afraid to use it until it goes dull and then experiment with different ways of sharpening it.

For a while on this knife I was running a 15 degree per side with no microbevel setup, and found that it would sometimes not cut very well, especially in paper, cardboard and similar fibrous materials. I then took then knife and added a 40 degree microbevel using only the medium sharpmaker stones and it cut this type of material much better.

So I would agree that a toothy edge works better for general purpose cutting, at least on H1.

[LC Kid]

Hi Folks!


80% of my blades have a very nice thooty edge.

The other 20% have the smooth one, those that I reserve for very detailed precision cutting tasks.

And of course my EDC ones are both, one main thooty edge and one smooth backup blade. :cool:

[phillipsted]

Generally, I find that I like toothy edges on high-carbide alloy steels, and smooth edges on carbon steel and simpler stainless steels. That's a general rule, and I usually have to fiddle around with each steel to see how it wants to be sharpened.

For instance, the S110v Mule was extremely toothy out of the box - to the point which it wouldn't cut thin paper cleanly. But it would slice through denser material like butter. It think the high carbide volume makes 110 a good candidate for a 600-800 grit edge. That's my initial plan, any way.

TedP

[razorsharp]

I usually use coarse edges... faster to do and last longer :)

a 600 grit hair whittling edge is really nice

[jackknifeh]

I usually use coarse edges... faster to do and last longer :)

a 600 grit hair whittling edge is really nice

I remember after I had the EP for a while I decided to find out how fine the grit needed to be to produce a arm shaving edge. At that time when a knife would shave my arm I thought that was all I wanted. I had the EP 120, 220, 320, 600 and 1k stones. This was about 3 years ago and I don't remember if I tried shaving my arm after the 120 stone or if I even used it. What I do remember is I shaved a patch of hair off my arm in one pass after the 220 grit!!! Also this was before I knew much about toothy edges or smooth edges, etc. I had been thinking the finer the grit the sharper the edge would be. :) When I realized a coarser grit would produce a shaving edge I was thinking "WHY USE ALL THE OTHER STONES?". :D Just remembering the questions I have had and learning the answers makes me realize how much I have learned in the past few years. I'll take credit for all my practicing. But WHAT to practice and HOW to do it? I give that credit to forums like Spyderco (mainly) and others with people so eager to share their wisdom just to help others. Prior to forums we needed to buy books (or more recently DVDs) to get the knowledge. Do any of you kids out there remember books? You can find them in museums. :D

Jack