Second toothy edge

[SHARPCO]

This is my second toothy edge. 


   
120 grit Norton Blaze

   
3M Scotch Brite belt Medium - 1 pass each side
and 
3M Scotch Brite belt very fine - 3 pass each side

   
Clean leather belt - 5 pass each side

   
Draw the edge through a wood block - 15 times




I think that if I make a toothy edge with a belt grinder, the blade must be wear out quickly.(My belt grinder Viel S5 is faster than Kally.) So I'll make toothy edge with 140 grit Atoma next time.

[grepper]

Great microscope work!  I appreciate how time consuming it is to do that testing, take images and post, so thanks for sharing.

These two images are the bottom half your images (burr side).

This one is after the Scotch-Brite.  Of course looking at microscope images is a bit of an art form, but it looks to me that there is still the complete top part of the burr with LOW at the bottom.

   

After the leather belt it looks like the top part of the burr is completely removed and much of it is completely burr free!  It looks like there are a few areas when that pesky, hard to remove LOW is still there, but for the most part that's a pretty good job of burr removal, especially considering how difficult some of that tough portions of LOW are to remove.  

   

That is one extremely gnarly, toothy edge.  Tomato skin, or much of anything else for that matter wouldn't stand a chance.

Your scope work does a great job of showing the burr removal process.  Thanks for taking the time to share that with us!

What sharpness reading did you get from that beast?  If you happen to test on a clean area of the blade I suspect it will be pretty good, but if you happen to test right on one of those lumps of LOW it will vary considerably.

[SHARPCO]

Thank you grepper.

That images are sequential. In other words, LOW was not completely removed even though all of the processes were completed. Even in some sections, I can see burr in the naked eye. So I think this was a failure.

I checked the BESS score after about 20 hours, it's 535 BESS.

I think both Viel and Kally is too fast to make toothy edge. Next time, I'll use Atoma 140 grit, and leather belt.

[grepper]

"Even in some sections, I can see burr in the naked eye."  It's amazing how reflective and easy burr is to see when you get the light just right.

"So I think this was a failure."  Personally, I wouldn't call it a failure.  It was an experiment, a test and I'm sure you learned from it.  Now you really know that it means to make a 120 grit edge with a Viel and try to remove the burr.  Now you've "been there, done that" and have personal experience and even microscope images to back it up.  I think your test is cool and made for a great post.  For me at least, every time I sharpen a blade it's a learning experience.

I've found the same thing you have insofar as burr removal gets very difficult with coarser than 150 grit.  I've found that very light pressure helps when sharpening with very coarse grits.  

It was working with big tough burrs that got me to play with using Scotch-Brite (SB) to remove them.  From my experience, I would skip medium SB belts.  They are too aggressive and can quickly chew up the edge resulting in a dull edge.  You might try sticking with extra fine SB belts and playing around with more/less pressure when doing burr removal.  

It looks to me that you got a lot of the burr and LOW off the edge but it just got too chewed up from (probably) the medium SB belt.  It would probably also help to use something less coarse than 120 grit for the sharpening part.

A couple of hours ago I sharpened an 8" Victorinox chef's knife using 150 Cubitron, deburred with extra fine SB and finished with the rough side of a plain leather belt.  Deburring took a few minutes but I got most of it all off.  Took 3 sharpness readings from handle to very near the tip.  140, 145, 170.  I'm sure I could have played more at the tip as I could see spots where there was still some burr.  Getting a bit slopping in my old age I declared it perfect! That blade is plenty sharp and I won't ever notice the 30 point difference or a tiny bit of left over burr whilst slicing some onions.

[SHARPCO]

" 140, 145, 170"  Amazing! I know some YouTubers who makes similar score with mirror polished edge. I believe it is much harder to make a proper toothy edge than a polished edge.