Sliced a tomato then sharpened the knife

[grepper]

Our garden is producing deliciously sweet Early Girl tomatoes, and what could be better than BLT sandwiches.  Proceeding to slice a tomato with a Victorinox Fibrox 5” chef’s knife, I noticed that the knife seemed a bit dull as I actually had to apply more pressure than just the weight of the knife.  Can’t have that.  Even though the slicing experience was a bit lacking in joy, I experienced a warm giddiness in the realization that one of my knives actually needed sharpening!  
 
The blade didn’t seem super dull.  I didn’t mash the tomato but required more slicing motion and pressure than I enjoy so I was curious as to its sharpness.  I took four measurements with the PT50B from tip to heel and was befuddled and surprised by the results which were: 500, 580, 995 and 755.  It didn’t seem like it had been that long since I last sharpened that knife, but those are the numbers.  When I tested the 995 part of the blade, I thought I might have to stick a cheater pipe on the handle to get enough leverage to force it through the test media.
 
It’s a bit of a head scratcher to me that the knife performed as well as it did.  Methinks it cut as well as it did because it’s a light weight and thin blade sharpened to a fairly acute 15°.  Nonetheless, I would have thought a knife that dull would have not cut so well.
 
I sharpened the blade with a Cubitron 150 grit belt on my Kally 1SM with an adjustable knife rest.  It only took one light pass to raise a tiny burr over 80% of the edge.  I couldn’t see a burr in a couple of small sections, but after gently touching those areas again to the belt there was a fine, even, barely visible burr the length of the blade.  Doing the other side of the blade was about the same process.  About 1.5 passes per side.  It took a minute or two to complete.
 
Deburring was done using a very fine Scotch-Brite belt.  Two light passes each side.  I noticed a bit of burr remained in a couple of small sections of the edge, so I dragged my fingernail along the edge of those areas.  Most of the burr fell away like snowflakes, and a couple of quick light to touches to the belt on those areas finished the job.
 
I finished with two light passes on each side of the blade using the rough side of a Surgi-Sharp leather belt.  The belt was treated with a bit of oil a long time ago, but no secret sauce or compound.  Basically just plain leather.  The blade seemed sharp to me, so I took four readings: 165, 115, 105, 95.   Just for grins I touched each side of blade around the tip where it had measured 165 to the leather belt one more time.  This time: 110, 115, 105, 95.  Done!  Now I don’t even have to slice tomatoes.  They just cleave themselves into neat slices when they see the knife coming.
 
The 150 grit Cubitron produces a nice toothy edge.  The Scotch-Brite belt deburrs quickly and easily without smoothing the toothy edge.  The two very light pressure passes on the leather, as far as I can tell, just finishes and cleans up the edge a bit and does not burnish or smooth the edge due to the extremely light pressure used and only two passes each side. 
 
After years of experimenting with sharpening, that’s the process I currently use.  It’s very quick and easy with repeatable results.  Producing a polished edge is a bit different, but rarely do I desire a polished edge.
 
Here is a picture of the knife and the Kally setup.

Victorinox Fibrox 5" Chef's knife:
   

Kally 1SM with KallyRest:
   

[Ken S]

Grepper,
Another informative, solid post with good humor. I would expect no less from you!
Ken

[SHARPCO]

Very fine scotch brite? Was it blue? How about super fine?

[EOU]

Thanks for your "tomato"  post here Grepper and also thanks for the sharpening primer contained within. For someone who is just getting into the hobby or trade - please go back and reread Grepper's post. It outlines just how simple and fast producing really sharp edges can be.

So what's that we see in the photo at the bottom of your post Grepper? Could that be a continuation of your efforts to build the world's best Kally knife rest? We won't pull anyone's leg here - we know that it is. That is a super nice looking rest and hope that you will share more info with the Exchange when you're ready.

 SHARPCO - We're proponents of using Scotch Brite belts for burr removal as well. Whatever the finest grade available is - and we believe that super fine is, that's what we use. Of course the coarser grades remove burr as well but do so at the expense of sharpness. The claim to fame for Scotch Brite is two-fold; it's fast (usually three or four quick passes each side) and doesn't remove the "tooth" from toothy edges. Take that back - three-fold; remember LOW (line of weld)? A Scotch Brite belt mounted on a Kally quickly and effectively removes LOW.

[SHARPCO]

EOU

A few months ago, I tested burr removing with Scotch brite belt(very fine = blue) after grinding with Blaze 120 grit. However I wan't satisfied. Maybe I need more practice. Thank you.

[grepper]

Mr. Sharpco - Yes, the one I use is a well used blue one. I think it is very fine. I didn't use a super fine only because I couldn't find a 1x42 at the time. For me the trick is a very light touch. Too much pressure and it will dull the edge. Too little and it does not work. I think you are right in that it requires some experimenting and practice, but done right it works very well. Well, at least in my experience. YMMV I guess.

[grepper]

Mr. Sharpco, Now that I know you are doing polished edges I probably would not recommend Scotch-Brite as it would scratch the edge. Additionally with a polished edge the burr is much smaller and more refined as finer and finer abrasives are used to polish it and might not benefit or even need the somewhat brute force Scotch-Brite method.

Sorry, I do so few polished edges I didn't consider it when I was thinking about it.

[SHARPCO]

grepper.

Thank you. My customers prefer polished edge than toothy edge, but I interest in it. Someday, customers may want it, too.

[SHARPCO]

grepper.

Your toothy edge is very aggressive.

IMHO, it's good at utility knives. But many people said finishing 1000 ~ 2000 grit is the best for kitchen knives. Because the coarser the edge, the faster the food loses its freshness. And if it is carbon steel it will easily rust.

How do you think about it?

[grepper]

I don't know about the food freshness thing, but you speak of the toothy edge like it's a tree saw.  Even though the edge is toothy, the "teeth" are extremely small requiring a microscope to see the uneven edge.  I find it hard to believe it could effect food freshness.  The edges are very sharp and slice beautifully.

As far as rusting, maybe at a theoretical level because there is microscopically more surface area right on the edge.  But for all practical intents and purposes I wouldn't think it is a concern at all.

In your case I suggest simply providing your customers with what they want.  They will be happy and you won't have to worry these theoretical minute details.   If you want you could give them a couple of toothy edges to try.  They will either like it or not and you can proceed from there.

Toothy or polished is a simply personal preference and the pros/cons have been endlessly debated. Some folks like me prefer toothy, others enjoy polished.