Duplicating the Lasting Cut Chef's Knife Edge

[grepper]

A short time ago Max (The Knife) sent me a Lasting Cut 8” chef’s knife to test for sharpness.  Not only was I was impressed at how sharp it was for a $12.00 knife, but also by how wonderfully gnarly and toothy the edge was.  It was about perfect for a kitchen knife and would have no problems melting through tomato, broccoli stem or citrus skin.  So, I wanted to duplicate that edge finish.  This is the story of my first attempt.

Thank you Mr. pjwoolw for pointing me to Deerfos ceramic belts!  I believe Deer’s are my new favorite.  I love the way they cut; smooth as silk and aggressive, they create a very even grind with a wonderful “feel” whilst grinding.  I’m almost giddy.  For this attempt to duplicate the Lasting Cut edge, I decided to use a 1x42, DEER JS 997 Blue Ceramic J-Flex Cloth Belt, 180 grit. 

This knife is my victim for the experiment:


 
 This is the edge of the Lasting Cut blade I wanted to duplicate:


 
Keep in mind that I took the belt out of the box and had at it, so the belt is still pretty hot, fresh and gnarly.  I’m sure the results would be a bit different after the belt calms down from use.  Nonetheless, here’s what happened:
 
I threw the knife on the old Kally 1x42 and sharpened the blade producing a small, even burr.  It was a very thin burr and easy to crush, but very malleable.  It ended up being somewhat difficult to remove as it was very resistant to fracturing off due to fatigue.  It was easy to see with the naked eye.



I apologize that I did not spend much time getting the lighting just right on the following microscopy, but I think it’s good enough to tell the little story.

The next two images are taken at about 200X.  The two images are identical except that the first was with top lighting and the second image bottom lighting to avoid all the reflection from the burr.





I threw it on the PT50B and got 425g.  That was to be expected as I was mashing the test media against the burr crud covering the edge of the blade.
 
The following four sharpness measurements represent 20 strops each on my jeans on my thigh.  I’m counting one strop as (strop one side + strop other side) = 1 strop.
285g
305g
250g
245g
 
It was obvious that I had maxed out effectiveness of my thigh/jeans stropping but I was disappointed.  Thinking it should be sharper, I threw the blade under the microscope.



What a disgusting mess!  There are still piles of burr on the edge, and some has been simply smashed down over the side of the bevel.  Sadly, my thigh/jeans stropping was: FAIL! 

So I caved and threw a leather belt on the Kally, rough side out and stropped.  There was a very small amount of left over 1u-3u compound on the belt, but very, very little.  It took a good 10-15 light passes on each side before I could no longer see any burr.  Then I gave it 10 quick strops on my jeans to remove any bits of crap that came off the leather just to clean the edge up, and tested the sharpness.  This time:
 
155g

Perfect!  Exactly what I was going for.  But I was worried.  Did I obliterate the glorious toothy edge with all my stropping?  With trepidation, I threw it under the scope:
 


No! I did not ruin the toothy edge!   Still wonderfully aggressive and toothy!  Outstanding.  It melts through paper towel and cleanly cuts dry garlic skin laid flat on a cutting board without breaking or tearing it.  Of course it push cuts paper, etc.  
 
Now, compare that with the Lasting Cut edge shown at the start of this post.  I used a 180 grit belt for this test, and it looks to me that the Lasting Cut was ground with something more coarse, possible 120 grit?  But really, I don’t care!  I think this blade will probably perform very well, and I consider my duplication attempt a success.  I don’t think I need to go to a coarser grind, but I might give it a try just for grins.

So, how sharp is the knife?  I was removing the knife from a small vice I use to hold the knife solidly under the microscope when my finger ever so lightly brushed the tip of the blade.  I was instantly notified with that “special” feeling from my finger.  Upon examination, sure enough, epidermal leakage!!!  DOH! 

[MaxtheKnife]

A short time ago Max (The Knife) sent me a Lasting Cut 8” chef’s knife to test for sharpness.  Not only was I was impressed at how sharp it was for a $12.00 knife, but also by how wonderfully gnarly and toothy the edge was.  It was about perfect for a kitchen knife and would have no problems melting through tomato, broccoli stem or citrus skin.  So, I wanted to duplicate that edge finish.  This is the story of my first attempt.

Thank you Mr. pjwoolw for pointing me to Deerfos ceramic belts!  I believe Deer’s are my new favorite.  I love the way they cut; smooth as silk and aggressive, they create a very even grind with a wonderful “feel” whilst grinding.  I’m almost giddy.  For this attempt to duplicate the Lasting Cut edge, I decided to use a 1x42, DEER JS 997 Blue Ceramic J-Flex Cloth Belt, 180 grit. 

This knife is my victim for the experiment:


 
 This is the edge of the Lasting Cut blade I wanted to duplicate:


 
Keep in mind that I took the belt out of the box and had at it, so the belt is still pretty hot, fresh and gnarly.  I’m sure the results would be a bit different after the belt calms down from use.  Nonetheless, here’s what happened:
 
I threw the knife on the old Kally 1x42 and sharpened the blade producing a small, even burr.  It was a very thin burr and easy to crush, but very malleable.  It ended up being somewhat difficult to remove as it was very resistant to fracturing off due to fatigue.  It was easy to see with the naked eye.



I apologize that I did not spend much time getting the lighting just right on the following microscopy, but I think it’s good enough to tell the little story.

The next two images are taken at about 200X.  The two images are identical except that the first was with top lighting and the second image bottom lighting to avoid all the reflection from the burr.





I threw it on the PT50B and got 425g.  That was to be expected as I was mashing the test media against the burr crud covering the edge of the blade.
 
The following four sharpness measurements represent 20 strops each on my jeans on my thigh.  I’m counting one strop as (strop one side + strop other side) = 1 strop.
285g
305g
250g
245g
 
It was obvious that I had maxed out effectiveness of my thigh/jeans stropping but I was disappointed.  Thinking it should be sharper, I threw the blade under the microscope.



What a disgusting mess!  There are still piles of burr on the edge, and some has been simply smashed down over the side of the bevel.  Sadly, my thigh/jeans stropping was: FAIL! 

So I caved and threw a leather belt on the Kally, rough side out and stropped.  There was a very small amount of left over 1u-3u compound on the belt, but very, very little.  It took a good 10-15 light passes on each side before I could no longer see any burr.  Then I gave it 10 quick strops on my jeans to remove any bits of crap that came off the leather just to clean the edge up, and tested the sharpness.  This time:
 
155g

Perfect!  Exactly what I was going for.  But I was worried.  Did I obliterate the glorious toothy edge with all my stropping?  With trepidation, I threw it under the scope:
 


No! I did not ruin the toothy edge!   Still wonderfully aggressive and toothy!  Outstanding.  It melts through paper towel and cleanly cuts dry garlic skin laid flat on a cutting board without breaking or tearing it.  Of course it push cuts paper, etc. 
 
Now, compare that with the Lasting Cut edge shown at the start of this post.  I used a 180 grit belt for this test, and it looks to me that the Lasting Cut was ground with something more coarse, possible 120 grit?  But really, I don’t care!  I think this blade will probably perform very well, and I consider my duplication attempt a success.  I don’t think I need to go to a coarser grind, but I might give it a try just for grins.

So, how sharp is the knife?  I was removing the knife from a small vice I use to hold the knife solidly under the microscope when my finger ever so lightly brushed the tip of the blade.  I was instantly notified with that “special” feeling from my finger.  Upon examination, sure enough, epidermal leakage!!!  DOH!

excellent

i like it......thanks

[Mark Reich]

I wanted to try a maximum tooth edge recently. I compared it to an identical S35VN blade finished on 8um poly diamond on a leather hone, which was tree topping and face shaving sharp.

I used a half worn 120 grit belt on a 2x72, and lightly removed the burr with a 400 grit Atoma. Just a few a few passes on 18um diamond compound on leather to really clean it up.

Wow, what an amazing difference! I used a regular heavy blue paper shop towel, crumpled into a ball in my hand (it's not unusual for me to test an edge this way).

The max tooth blade sliced about 3x more deeply than the refined blade!

Both blades were shipped immediately, so I didn't do a definitive wear evaluation. I'm looking forward to repeating this with S35VN and M4, since I have many more identical blades.

Here is the sticking point. When anyone gets a new knife, they want to see it shave arm hair beautifully. My maximum tooth didn't shave much at all, nor should it IMHO.

I've about decided that a 1k stone followed by 18um poly diamond on leather is the answer with good, hard steel.

For inexpensive stainless kitchen knives, I still think 150- 220 grit is going to cut more tomatoes.

[grepper]

Mr. Mark, Yes!  You’ve found the exact same results as I have.  In reality, a toothy edge is far more useful than a polished edge for most purposes, except for things like shaving and slicing sashimi.
 
I’ve found many times when even a very sharp polished edge just does not work.  One time my wife was trying to cut some plastic rope.  I gave her a freshly sharpened, polished edge knife and proudly said, “Here, use this!”   The knife was basically useless and just rode on the surface of the rope strands. 
 
A friend who witnessed the event then mockingly said something like, ha ha, your knife can’t even cut rope!  As you can imagine, I almost lost all will to live!  My freshly sharpened blade was an abject failure.  I felt!
 
I’ve seen many times cutting things like tomatoes where a very sharp polished edge will only squash the tomato.  But pierce the skin with the tip of the blade and then it slices through well. 
 
A sharp, very toothy edge should shave just fine.  Blades sharpened @ 180 grit shave very easily without problems, and I don’t see why a 120 grit finish should be any different.  I’ll have to give it a try to be sure though. 
 
I’m guessing one of two things must have been happening:
 
1.  There was still burr.  Burr can be very deceptive with a toothy edge.  Hunks of burr can act like a saw and tear away at what you are cutting.  The burr can be very difficult to detect without looking at the edge under a microscope.  When I get some time I’ll post images showing this.  In my opinion burr is much more difficult to completely remove than most folks think.
 
2.  The edge was just not sharp.  Maybe you didn’t get all the way to the edge with the abrasive?
 
I’ve grown to dislike polished edges except in very specific cases such as push cutting application for chisels, axes, cleavers, etc., or knives used for specific purposes.
 
I can see where that’s a problem for knife makers, especially selling to someone who really does not understand the ramifications.  A lot of people think a perfect mirror bevel and edge, sharp as a razor is a good thing.  What they fail to understand it that for general use, an over sharpened edge is weak and a polished edge is just not that useful.  It sure looks impressive and very pretty sitting in a glass display case though!
 
It reminds me of the old saying:  A ship is safest in harbor, but that’s not what she’s built for!

[Rupert Lucius]

Inadvertently created a toothy edge on a 3" paring knife (Warther) S35VN.

Small nick in the radius of the knife about one inch from the tip was what I wanted to remover.

Maybe my Son  will send a photo(s) using the scope that Grepper suggested.  Excellent camera Grepper, thanks.

Having always sharpened my S35VN knives on belt machines running Trizacts.  No problems none!

I, placed my triangular diamond rods into my Spyderco Sharpmaker 204 - off to sharpening - within a few passes things really happened (bad, bad things) - I, handed my project off to my Son to repair on his EPP.

Last evening I see this:

rickleeo • a month ago

• why is the diamond stone set not recommended for powder steels?
  
  
  Gritomatic Mod rickleeo • 23 days ago
  
  
• Diamond grains creates large groves and micro chipping on the edge when coming in touch with hard carbides of powder steel.
  

I,  failed to receive the  above info.  Guess I had been asleep at the switch?

Rupert

[Mark Reich]

All I could ask for is something tangible, like a micrograph.

I hear all sorts of opinions, never heard of any evidence.

As someone who's been using diamond plates for many decades, they've always worked well for me.

Many people would say that diamond plates are the only thing that works with such abrasion resistant steel. I would definitely be leaning in that direction. 

In actuality, the only things harder than a vanadium carbide are CBN and diamonds, so it's more reasonable to say that you Better be using diamonds if you expect to affect the carbides. Otherwise you're just kind of polishing them.

Now that we have come to some conclusions regarding tooth in relation to grit, we find that 400 grit is pretty fine. Keep that in mind. 

Vanadium carbides are generally recognized as the smallest carbides. I've read that they are 2-4um in modern powdered steel like S35VN. 

If the carbides are 2-4um, and you have a 400 grit scratch pattern, one scratch would be 10-20 vanadium carbides DEEP (400 grit happens to be about 40um). 

It's difficult for me to fathom how completely irrelevant a 2-4um "hole", from tear out or chip, would appear on a 400 grit scratch pattern. 

The thing that I really don't understand is why I never see micrographs that show what micro-chipping or carbide tear out actually Looks like!

Mr. Rupert, I don't believe you've been missing Anything.

[MaxtheKnife]

yesterday i picked up one of my rental knife accounts:.. ......a set of 11 mixed beater knives, mostly dexter & lasting cut.

three weeks ago i sharpened all of them on 150 grit ceramic and then leather only.....nice and sharp.  i was really curious as to how they would hold up after three weeks at a busy restaurant.  most of my rentals are for three week periods, but in the past, i have always sharpened them to A30/600 grit finish.

all i can tell you is the 150 grits after three weeks held up much nicer than the 600's ever did.......many of the 150 grit are still pretty sharp and useable............i like it

i have 4 more rentals still out sharpened the same way, so i will have more results soon.

CUT MATERS GREAT TOOOO

[Mark Reich]

Thanks a bunch for sharing your experience, Mr. Max!

[Rupert Lucius]

Max

Did you apply anything on the leather?

Rupert

[grepper]

Mr. Max, Thanks for the great report.  I especially liked the real-world use edge retention test.  Actual use is the most valuable test method.  Frankly, I’m not surprised at the results.
 
+1 for a toothy edge!  I’ll bet the restaurant folks really liked it.  I suspect the 150 grit was pretty close the Lasting Cut edge.