The Toothy Truthy (one version) ;D

[Mark Reich]

I've really been getting into sharpening with ever coarser grits lately in response to Mr. Grepper's quest for tooth. It's been an interesting study.

I know Mr. Grepper and others are mainly focused on belt grinders, but the only way to get a clean edge with a coarse belt will be by honing on a stationary belt. Even a Kally vaporizes steel instantly at 150 grit, and it's totally impossible to get a clean edge. The worst part about even trying this on a grinder is how quickly you will run out of blade. It might not mean much on cheap knives, but you won't get many sharpenings on a Spyderco before you will notice your blade shrinking (been there, hate it).

*This might be possible with a super low speed Viel!* Parts for mine are coming soon via Mr. Rupert, and I'm truly looking forward to finally meeting Mr. Viel on steroids! 

Anyway, I don't know if y'all sharpen freehand, but I can get a totally clean edge on very coarse stones. Last night I used a 140 grit Atoma diamond plate to sharpen a "known" blade. I've been using this knife for several years. It's good old 52100, with my normal heat treat. 

I have to admit, it was not easy getting a totally clean edge off a stone this coarse. It definitely requires all the skill I possess, and took me about half an hour to accomplish for the first time. I honed at 90* to the entire edge on the Atoma with Zero pressure. I removed the very minor wire edge/burr by slicing through leather, and I "stropped" on my palm to remove leather debris, and anything that didn't look like clean teeth at 30x magnification. 

I was stunned with the result. I would not have guessed how sharp 140 grit can be. Push cutting paper? Sure enough! Unbelievable! Bess scores with my KN100 were kinda ragged though, from 130s to 180s along the length of the blade. This was after slicing and push cutting a few feet of thick cowhide.  

I'm going to EDC this knife full time, and only touch it up on the 140 Atoma. Nothing else. No refining or "cleaning up" of the actual scratch pattern will occur. I'm going to let nature run it's course, and let the chips fall where they may. 

I'm using 52100 because it's what I normally use, and I'm not going to waste time on steel that won't hold up to this difficult mission. This is one of the most challenging and unique tests I've ever done. It certainly ranks right up there with splitting hair, but with the added practicality of holding up and touching up under normal use.

I did receive a large box of belts from Tru-Grit today, with the 1x42 Blaze and Cubitron IIs in there somewhere, but I also ordered two different types of 60 grit stones last night. IMHO, stones are way more accurate and manageable for a project like this. I don't want to grind on my knives with these coarse belts until I have a machine that's capable, but I'm really looking forward to it!

[grepper]

Very interesting Mr. Mark! 
 
I routinely get blades 150g or sharper using 80 – 180 grit belts.  Not a problem.
 
“I was stunned with the result. I would not have guessed how sharp 140 grit can be. Push cutting paper? Sure enough! Unbelievable! Bess scores with my KN100 were kinda ragged though, from 130s to 180s along the length of the blade. This was after slicing and push cutting a few feet of thick cowhide. “
 
Yes!  And that blade will never just ride on the surface of things like nylon rope, plastic, tomato skin and the like.  I’ve found no problem shaving hair either, but being so toothy it’s not a shave for delicate skin or the faint of heart!
 
I just received some 120 grit Cubitron II belts and sharpened a blade.  I too was amazed by the results.  140g sharp and the blade slices through everything I can find to cut.  No problem slicing through a 3/4" roll of newspaper cleanly.  No riding, just easily slicing through.
 
I also have some 150 grit Cubitron (not Cubitron II) belts coming this week.
 
I have a bunch of comments on your post Mr. Mark, but it will take some time to compose.  I’ll post more on that later.  I will also post much more on my own results and include microscopy and sharpness testing results.  Those comprehensive posts take a lot of work and time to do, so it will take some time to complete.
 
A question for you Mr. Mark:  When you say, “Even a Kally vaporizes steel instantly at 150 grit, and it's totally impossible to get a clean edge.”
 
What do you mean by “get a clean edge?”  Do you mean that it’s difficult to remove the burr?

[Mark Reich]

I'm going along for the ride, Mr. Grepper. I'm now well interested in the "League of Ginormous Tooth", or whatever you call it. 

A "clean" edge is just one with no wire or burr. Normally, one that's been "deburred", or "cleaned up" with some refinement.

How are you dismantling the burr from an 80 grit belt? Normally there's a significant burr from grinding, even with way finer grit. Especially with softer stainless steels, like almost all kitchen knives.

[grepper]

Mr. Mark inquired, “How are you dismantling the burr from an 80 grit belt? Normally there's a significant burr from grinding,”
 
You are not kidding about that!  Especially edge trailing and like you say with the soft steel of kitchen knives, those coarse grits produce big, tough, gnarly burrs that are indeed very difficult to remove without smoothing the toothy edge.
 
Here is what I do.  It works, but it takes some experimenting and little practice to pull off.  Once figured out though, it’s pretty quick and easy.
 
I use the rough side of a Surgi-Sharp leather belt on the Kally with a little bit of Tormek 1–3 micron honing compound.  I’ve found that dry leather does not work as well, so I guess that there is some abrading away of the burr happening as well as bending the burr to fatigue it off.
 
All of the work on the leather belt is done with very super light pressure to minimize any smoothing to the edge.   That Tormek compound is pretty aggressive, and it’s very easy to smooth some of the toothy edge if you are not careful.
 
First I do a couple of passes on each side of the blade at the same angle that I sharpened at.  This removes almost no burr, but just mostly straightens it.  The giant, gnarly burr is still completely visible just by looking at the blade.
 
Next I just barely touch the edge to the belt at almost 90°.  This mostly just touches the edge of the blade to the “fuzzyness” of the rough side of the leather belt.  Just enough to see the burr bend completely to one side, but not hard enough to abrade the cutting edge.  Then I do a quick light pass on the side with the burr at sharpening angle to straighten the burr and then repeat the almost 90° hone this time bending the burr the other way.  At this point I generally see the burr has started to be removed.
 
Then I just sort of mess around doing the same sort of things until the burr is removed.
 
The real trick is that all of this is done with extremely light pressure.  Sometimes just tickling the edge with the belt.
 
I was almost giddy when you said, “I honed at 90* to the entire edge on the Atoma with Zero pressure.”!  I didn’t think, and had not heard of anyone else doing that 90° thing.  I thought I was alone, totally alone in the universe doing something crazy like that.  But I have done sharpness testing and have found that when using something soft like leather with a super very light touch it does not seem to dull the edge.  In fact, unless you use abrasives to remove the burr, I’ve found it’s about the only thing that works.  Trying to deburr at the sharpening angle does not bend the burr enough to fatigue it so it breaks off.  I suppose it might after a really looooooong time, but I’m not up for that and it would no doubt smooth the tooth out in the process.  So I’m really surprised and happy to hear that you do the same thing.  It’s nice to know I’m not totally alone and completely crazy.
 
That all sounds like it takes a long time and is overly complicated.  But really, in practice, it does not take very long and it not difficult.  It just takes a little practice.
 
Anyway, it works and completely removes even those big, nasty, gnarly, tough, malleable and ugly burrs and seems to leave the edge very sharp and the toothy edge intact.

[Ken S]

Interesting thoughts. They will take some shop time to absorb.

While I was testing two CBN wheels (D-Way 80 and 180 grits) on the Tormek, I tried going directly from the CBN wheel to the Tormek leather honing wheel loaded with Tormek honing compound. I was surprised with both the improvement in BESS and the bevel smoothness. I would not normally sharpen a bench chisel this was, however, for "on the fly" sharpening by a turner, this quick method looked promising. It works wet or dry. (Use some Honerite Gold with the wet CBN wheel as a rust preventative.)

I also sharpened a kitchen knife this way. I do not remember the full procedure, nor do I remember what I have done since. (It was an after thought. I did the primary testing with bench chisels and a turning gouge.) The knife has been daily service since.

Ken

[Bobbo]

I am fascinated with this business of sharpening with such coarse grits. This doctrine is almost wholly confined to Edge On Up materials/videos and to a larger degree, this forum. I've tried it and it not only produces what I would call good results but, in my opinion, superior results for kitchen use cutlery. I have been limited in my experimentation to a Work Sharp and a modified Sharp Pad using different abrasives and grits via the local hardware store. I think I'm ready to step up to a Kalamazoo though. I don't expect sharper edges but I do expect sharp edges more quickly.

I'm a true believer now. I was going to use the term "convert" but before edge on up products and this forum I didn't know enough to be able to be called a convert. Raise a burr and then remove the burr. The essence of sharpening. Thanks to everyone for shedding light on this philosophy. I simply cannot express my appreciation enough.

[grepper]

When I first learned to sharpen, I did a lot of research and learned the same thing that I suspect that most people do.  Start with a coarse grit then go finer and finer until a smooth, polished edge is produced.  Then finish with some very fine honing compound to make a shiny, mirror bevel.
 
I can do that.  No problem.  I’ve said a bunch of times that a smooth, exquisitely sharp edge will cut just about everything very well.  But what I found was that the super sharpness didn’t last very long.  Soon, very soon, the blade started to ride on ripe tomato skin and other stuff like nylon type rope, broccoli skin and the like.  Very frustrating!
 
That’s what sent me on the quest for the perfect toothy edge.  There are times such as chopping and push cutting when a smooth edge is preferable.  But at least for me, I’ve found that for just about everything else, both in the kitchen and for general use, a nice toothy edge works much better and lasts longer.
 
Just for grins I did an 80 grit finish on a knife I use for various outdoor tasks.  It works great!  It cuts plastic, nylon rope, twine, cardboard, paper, plant roots and just about everything else I’ve thrown at it and never rides on the surface.  It just grabs on and cuts.
 
I too have noticed that there is not much discussion out there about the wonders of a toothy edge.  Strange, eh?
 
Thanks for the post Mr. Bobbo!  I find it very interesting that you too have found that a toothy edge works much better for kitchen cutlery.  Keep us informed of your experiences with what Mr. Mark has coined the, "League of Ginormous Tooth".    Cool stuff.

[Mark Reich]

I'm sorry Mr. Grepper, I had two failures to launch replying to you. Agonizing. Hopefully this will make a difference for you. This was the most important topic I had to talk about, and I hate that it took so long to formulate the response. I'm Absolutely in knife production mode right now, so sitting down for 15 minutes feels like I'm slacking off. 

You're never really very "alone" when it comes to sharpening, Mr. Grepper. Just hang out on good sharpening forums for a while. Hopefully this forum will continue  to grow, and become a well established forum. We have the BESS advantage of measuring sharpness.    I look forward to being here more than daily again by the end of August.

I offhandedly use "hone" more than one way, but in that context, to me it just meant "finishing with edge trailing strokes". It kinda seems to me like "sharpening" (edge leading or scrubbing steel off- creating the bevel) is basically creating the burr, and honing is removing the burr- usually edge trailing with refinement. Slight convexity helps, and you can cut a burr off with a couple edge leading passes easier with the ultra slow speed of stones. 

On stones or hones, when you're sharpening a curved blade, it's best to keep the edge 90* to your line of travel across the surface. It makes a difference, especially to guys with straight razors and stones. Or people testing tooth. 

Deburring with the Blade vertical to a horizontal stone (like how I think you understood me) isn't that uncommon. Most often I've heard of guys doing this with the 3 micron DMT. In theory it could give you a perfect 4000 grit tooth. I think it works better just bending the burr past 90* to the blade, then cutting it off Some try angling the scratch pattern or opposingly angled scratch patterns on each side of the blade.

For toothy edges, it's hard to beat diamond plates. I'm using an Atoma 140 like THIS to finish the edge. That's what allows me to cut the burr off precisely and quickly. 

I'm not sure I would put a 60 grit edge on anything else I own, but I thought a decent machete would be interesting. I even had a good independent observer, which I always try to take advantage of when I'm testing something. 

The machete was already sharp, so it only took one pass per side to get a good scratch pattern and flip the burr. The only thing left is getting it off- without Any polishing. Cutting the burr off very accurately, by hand, with a coarse, sharp stone is super effective. I had a nice thin blade with dynamic tooth.

It seemed to work pretty well. Many old rose bushes were trimmed, with many dead rose branches too. A bunch of sucker branches went down with strategic blows. I tested regular slicing on lots of stuff, but I was rather disappointed TBH. 

I took it back to the grinder and went to a 120 grit belt, then cut the burr off exactly the same way. Wow! That made a huge difference! All the rest of the pruning went like magic comparatively. I was zipping cleanly through everything, with much less energy and speed of motion. 

Slicing was different too. With the coarse edge it didn't matter if I was trying to slice straight through or trying to make a tapered cut. It took some sawing, and it wasn't easy to hold the branch. The coarse edge bit into the material aggressively, but it didn't result in easy separation of the branch. It took significant motion, and energy. The coarse edge resulted in much more drag and friction. It was a lot like cutting with a hacksaw, while the finer edge just did everything more cleanly and easily.

I did more test sharpening with the machete, and learned more about the burr. The most significant thing I learned is that Kallys run fast enough to create way Way more burr than I was getting at super low speed. In fact, edge leading or edge trailing didn't make nearly as much difference as belt speed. At about the speed of smell there basically was no burr.

[Ken S]

Mark,

I understand your frustration with posts which don't get launched. I was very happy to find the "save as draft" with post and preview. A second nice forum feature is being able to do a full edit. I use that when I get interrupted and want to post a thought. I can return later and add or edit. It's a good way to hide spelling oopses which sneak through.

I posted a topic about the save as draft option in the bottom sub forum. It is the only topic listed as ."normal". All the others are listed as "important". At least I feel normal, even if I am not important. 

Ken (more later)

[Mark Reich]

 I'll hang out with a normal guy rather than an important one most of the time.  

Thanks Ken, I read that when you posted it and thought, "That's good information!". I'm getting old and stubborn though. Actually I'm forgetful, but I'm old enough to get away with calling it stubbornness. 

Back to this serious business of mega-tooth. 

So far I've done little but reaffirm that anything coarser than about 120-150 grit is beyond toothy, in a few ways. 

Of greatest concern to me by far- It eats up too much steel! You can measure how much steel it takes to touch up, even as gently as possible. If you're sharpening at 1800 SFPM, that's a whole other ballgame. That's how you get burr you can't just feel, you can measure it with a yardstick.     Yeah, it sucks to remove. Especially with an 1800 SFPM machine. You Need Stones!! 

So who uses stones or diamond plates to gain... Teeth of Justice