# Durability Testing Shi.Han (AKA Ginrei) 240 Gyuto



## stringer (Jul 19, 2019)

I bought this knife a few weeks ago on a whim from Strata in Portland, ME. I picked this gal up and decided she needed to come home with me. In this thread I will detail how I prepare a knife for use in a professional kitchen.


Specs Before Sharpening:
Edge, Heel to Point, 247.5 mm
Spine, Handle to Point, 265 mm
Handle, 140 mm
OAL, 405 mm
Height at Heel, 55.9 mm
Spine, Thickness at Handle, 4.7 mm
Spine, Thickness at Heel, 3.9 mm
Spine, Thickness at Midpoint, 2.5 mm
Spine, Thickness 1 mm from Point, .8 mm
Thickness 10 mm behind edge at Midpoint, 1 mm
Mass, 229 g
61.5 HRC
52100 Monosteel
Hammered Kurouchi Finish








I gave the factory edge a week of home use. I wanted to get a feel for the knife and figure out how reactive it is. It started to pick up some patina. The factory micro bevel is very conservative. Kind of the opposite of the Watanabe approach. That Gyuto started off with a zero edge, s-grind. This has a pretty high v-grind with very slight convexity. And then a chunky microbevel.






My goal is to get rid of the micro bevel and establish a nice flat wide bevel that I can use as a sharpening road for the life of the knife. Through progressive sharpenings I will keep making that blade road steeper and the blade thinner until I start to see issues. Then I will add a micro bevel and slowly thicken it up until I hit a nice sweet spot between aggression and durability.

I applied some Sharpie so you could see what I was doing



I started sharpening with my Crystolon coarse oil stone. I start by focusing about halfway up the Sharpie mark. The micro bevel becomes very obvious. I do one side and then the other.




Once I get that established on both sides then I go a little flatter. Targeting the entire Sharpie mark.







Once I get to how far up I want to go, I shift my finger pressure down close to the edge and begin focusing on getting rid of the factory micro bevel and establish a burr. I continue working back and forth adding a little mineral oil here and there and occasionally reconditioning the surface with a big coarse hardware store silicon carbide stone.







To Be Continued


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## stringer (Jul 19, 2019)

My phone died so I wasn't able to get a bunch of pictures of the rest of the sharpening process. But the basic idea is, once you get a burr, you can go through your progression. I spend about thirty seconds on alternating doing back and forth scrubbing at each progression. After the crystolon I went to Shapton Glass 500. Then I went to Suehiro Deluxe 1000. From the 1k on I follow the scrubbing motion with 50-100 alternating edge leading sweeping strokes with very light pressure. I repeated that action, scrubbing and then sweeping. I did Shapton Glass 2k, 4k, 8k. Then I finished on a Hideriyama that I just picked up from JKI. The knife has a near mirror polish and looks pretty good. I've established a nice wide sharpening road. We'll see how it does in the real world over the next few weeks.














If you're curious. I haven't lost any measurable height yet at least measurable with my crappy digital calipers. I have trimmed off 4 grams of weight.


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## HRC_64 (Jul 19, 2019)

ooohh this looks interesting.... 




One quick question....

That rated-hardness for 52100 seems greared more toward toughness (58-59) vs retention or absolute geometry...




Curious to see how find this impacts the role of the knife in youre aresenal?


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## Barmoley (Jul 19, 2019)

Looking forward to more, great start. How do you know the hardness was this disclosed to you by the store or Sheehan himself?


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## HRC_64 (Jul 19, 2019)

BTW the aesthetic of this Shi/Han has always been an eycatcher IMHO...


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## stringer (Jul 19, 2019)

Barmoley said:


> Looking forward to more, great start. How do you know the hardness was this disclosed to you by the store or Sheehan himself?



Educated guess


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## stringer (Jul 19, 2019)

HRC_64 said:


> ooohh this looks interesting....
> 
> 
> 
> ...




The Watanabe is the only really hard blade I've used. It has taken some getting used to. My sweet spot is usually in that 58-61 range.


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## labor of love (Jul 19, 2019)

Barmoley said:


> Looking forward to more, great start. How do you know the hardness was this disclosed to you by the store or Sheehan himself?


I can’t seem to find the media at the moment. But I believe he mentioned at some point aiming for 58hrc.


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## labor of love (Jul 19, 2019)

Correction: he does mention his A2 KU line being 58hrc.


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## MrHiggins (Jul 19, 2019)

Stringer: you're doing it the hard way! I sent my Shi-Han A2 back to the maker for thinning. Shehan did a superb job. Took about 20 grams off.


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## stringer (Jul 19, 2019)

MrHiggins said:


> Stringer: you're doing it the hard way! I sent my Shi-Han A2 back to the maker for thinning. Shehan did a superb job. Took about 20 grams off.
> View attachment 57059
> View attachment 57060




Awwww. C'mon man. What's the fun in that? Nothing like a few hours with the Crystolon to keep your shoulders in shape.


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## MrHiggins (Jul 19, 2019)

stringer said:


> Awwww. C'mon man. What's the fun in that? Nothing like a few hours with the Crystolon to keep your shoulders in shape.


It'll make a man of you, no doubt!


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## Barmoley (Jul 19, 2019)

labor of love said:


> Correction: he does mention his A2 KU line being 58hrc.
> I think 52100 KU line is in the same ball park.


Oh that's interesting, never heard this. Very unusual for 52100 these days, as it is very tough even at higher hardness. I wonder what is the reason for this, will make it extremely tough, but edge retention will most likely suffer. On the other hand it should react well to
steeling and general abuse.


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## stringer (Jul 19, 2019)

labor of love said:


> I can’t seem to find the media at the moment. But I believe he mentioned at some point aiming for 58hrc.



I think it might be slightly harder. Coutelier has it listed at 62. Bernal has stuff in the same line listed at 61.


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## stringer (Jul 19, 2019)

Barmoley said:


> Oh that's interesting, never heard this. Very unusual for 52100 these days, as it is very tough even at higher hardness. I wonder what is the reason for this, will make it extremely tough, but edge retention will most likely suffer. On the other hand it should react well to
> steeling and general abuse.



There is an Instagram exchange where the Bernal guy says that with the A2 batch he left "a little retention and hardness on the table in exchange for easier sharpening and better cutting feel."

The cutting feel is supposed to be toothier I guess. 

I don't know for sure. The cutting feel is nice. Once I made it past the never ending micro bevel the burr pops up quick and easy on each stone and is just as easily chased away.


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## labor of love (Jul 19, 2019)

Fair enough. I think his 52100 feels unlike all the others I’ve tried. One way or the other he’s doing something different. In a good way.


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## labor of love (Jul 19, 2019)

MrHiggins said:


> Stringer: you're doing it the hard way! I sent my Shi-Han A2 back to the maker for thinning. Shehan did a superb job. Took about 20 grams off.
> View attachment 57059
> View attachment 57060


No you’re not getting off that easy! Let’s see the choil shot!


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## stringer (Jul 19, 2019)

I did another test chop after sharpening. Fun little chopper.


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## Bensbites (Jul 20, 2019)

I have a couple shi.han knives in the shop, they look really nice and the customer loves them. I also love seeing strata mentioned here. I have felt with Evan in several occasions and look forward to meeting him in August.


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## JBroida (Jul 20, 2019)

stringer said:


> I think it might be slightly harder. Coutelier has it listed at 62. Bernal has stuff in the same line listed at 61.



He’s literally said his goal is 61.5... I think both bernal and coutelier are close enough for government work


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## Barmoley (Jul 20, 2019)

Thanks Jon, this makes a lot more sense and is good to know.


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## stringer (Jul 20, 2019)

The original finish looked mostly done with very fine belts. Patina set in very slowly and was mostly grays with a few brown spots. Unsurprisingly, the near mirror finish is quite a bit more reactive and the colors are much more vivid. All I cut was one onion.


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## MrHiggins (Jul 20, 2019)

labor of love said:


> No you’re not getting off that easy! Let’s see the choil shot!


The masses demand choil shots, and choil shots they shall get!

I asked shehan to focus on thinning the front half of the knife, so I don't think the choil shot tells the whole story. I also said that he took 20gr off the weight. Now I'm doubting my accuracy (that's what I think I remember, but my memory on these things is suspect).

In general, this knife has been a bit of an ongoing work in progress. When I first got it, I thought it was too forward-balanced. I tried to correct it by replacing the standard ho wood handle with something bigger and heavier (Cody Paul did a great job with a gidgee and blackwood handle). It still didn't quite fit my preferences, so I asked shehan to thin it. When I got it back, I cut off about an inch of the handle. Unfortunately, I exposed the handle's interior dowel when I did. It's not as pretty now, but it's exactly where I want it in terms of performance.


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## Midsummer (Jul 20, 2019)

Thanks for documenting your journey with this knife. My efforts pail in comparison. You clearly have much more experience in maintaining your blades. I want to thank you for sharing.


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## bm11 (Jul 20, 2019)

Cool thread! Excited to find Strata- I had never heard of it before, but they are only just over an hour from my house. I reached out to them already!


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## stringer (Jul 20, 2019)

Here's the choil on mine.
This is after sharpening but it should still look pretty much like it came because I didn't focus much on the heel.


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## panda (Jul 20, 2019)

ive always wanted to try a shihan, but i cant with that profile..


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## MrHiggins (Jul 20, 2019)

panda said:


> ive always wanted to try a shihan, but i cant with that profile..


Profile pic of Shi-Han white #2/wrought iron (260x57) and Shi-Han A2 (240x53).


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## HRC_64 (Jul 20, 2019)

I'm with Panda I can't get my head wrapped around Shi.Han profiles.


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## labor of love (Jul 20, 2019)

HRC_64 said:


> I'm with Panda I can't get my head wrapped around Shi.Han profiles.


He’s making me a gyuto with a custom profile. Flatter profile+lower more pointy tip.


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## zizirex (Jul 20, 2019)

stringer said:


> I bought this knife a few weeks ago on a whim from Strata in Portland, ME. I picked this gal up and decided she needed to come home with me. In this thread I will detail how I prepare a knife for use in a professional kitchen.
> 
> 
> Specs Before Sharpening:
> ...




Nice Job. I saw Shi Han last time, it is really thick and hefty but not so thin behind the edge. 

So, how good is the Norton Crystolon? because I am looking for really coarse stone, and I saw guy swear by it because it cuts fast and doesn't dish easily (I saw one guy use it to fix Kanna bevel since it stays flat.) Is it cut faster than Shapton 120? or slower...


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## stringer (Jul 20, 2019)

zizirex said:


> Nice Job. I saw Shi Han last time, it is really thick and hefty but not so thin behind the edge.
> 
> So, how good is the Norton Crystolon? because I am looking for really coarse stone, and I saw guy swear by it because it cuts fast and doesn't dish easily (I saw one guy use it to fix Kanna bevel since it stays flat.) Is it cut faster than Shapton 120? or slower...



I agree with your friend's assessment.
I really like the crystolon. I haven't used any Shapton beneath the 500. The other coarse stone I have is King 320. It's definitely faster than that. It stays flat even if you really bear down on it, which I don't believe is true for those other coarse options. The abrasive requires refreshing pretty frequently. I use a $3 silicon carbide brick from the Asian supermarket. It works great and it's easy to remember to keep it and the crystolon separate from all my whetstones and diamond plates. The feel and the sound, while not pleasant, aren't as bad as using diamond plates.
A few other drawbacks. It's messy. If you get too much oil it's easy for your finger to slide off and slice itself. The scratch pattern is pretty coarse. It might take more work to get rid of it if that matters.
It's definitely my favorite for thinning at the moment.


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## DisconnectedAG (Jul 25, 2019)

Dude, this is an awesome freaking thread. Thanks so much. I've only started to thin, and this helps so much. You're my hero!


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## Wdestate (Jul 25, 2019)

HRC_64 said:


> I'm with Panda I can't get my head wrapped around Shi.Han profiles.



In what sense?


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## stringer (Jul 25, 2019)

The continual radius edge with upswept tip never appeals to me looking at pictures. But I'm willing to admit in public that in my hand it feels great. To me that's all that matters. I am a fan of giant santoku front ends. I love my Watanabe. I'll probably pull the trigger on a Takeda someday. I'm definitely going to try a Masashi. If I hadn't of bought this knife I probably would have picked up one of the upswept Mazakis that have recently been in clearance in the BST aisle.

A thin pointy tip on a gyuto is a liability for me. I have a whole selection of sujihikis and petties with thin tips if I need one. I've been known to break even the most child proof tip. Usually from doing something stupid.
I lost about 10 mm of the tip of the Watanabe slicing a couple of water bottles in half. So now it has even more of a killer whale snout. I still enjoy it. The Shi.han feels more sturdy, stiffer, but less brittle at the edge. I'm going to do some test videos tonight. We'll see how she does.


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## stringer (Jul 25, 2019)

My wife's out of town so I'm making my dinners for the week. Stir fry ground beef and cabbage and boiled chicken. So these will be my test ingredients. I'm using a brand new rock hard textured white plastic board. These are in my opinion the worst for your edges outside of something really stupid like glass or marble. But it's what I have to use at work so if we're going to do a durability test, we'll use the real thing.













Cabbage
This thing is an amazing slicer. It's not the greatest push cutter. At least not yet. I will definitely keep thinning for awhile. There's no shoulders left. But it's still a little thicker behind the edge than I would like.



Red Onion

Slicing and dicing. Feels very confident and precise.



Carrots

I go slow and user the whole blade to demonstrate the grind. It has nice subtle convexity that I was able to maintain in my thinning. It definitely wedges a little but it handles the slicing and julienne quite nicely.




Chicken
So this was one of those mutant chickens from outer space. I had chopped up all the veg and really banged hard on the board and no damage so far. So I decided to test it with some chicken ribs. It definitely survived better than the Watanabe would.



The knife held up pretty well. Only some extremely tiny nicks that came after I got mad at the chicken for not self dissecting. Upon closer examination they are little deflections more than nicks. Might come out with a light strop. The light glints are the impacted areas. Hard to photograph.






Dinner came out good anyways


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## panda (Jul 25, 2019)

that cabbage look tasty yo


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## stringer (Jul 25, 2019)

panda said:


> that cabbage look tasty yo



The cabbage is pretty good. The chicken is even better. I've been doing the David Chang hot pot style boiled chicken lately. Cook the whole chicken until it's falling apart. Pull out the bones and shred the meat. I'll eat it with rice.


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## Barmoley (Jul 25, 2019)

This is very cool. Thank you very much for doing this review, we need more of these.


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## stringer (Jul 25, 2019)

So I tried stropping it on pasted denim. Several of the micro chips turned into actual chips. They are still it hard to see with just a normal picture. This one is zoomed in and the contrast is cranked up.







Here's a look with video. Patina is coming in nice.




I won't use this knife for spatchcocking chickens. It just would have been a pretty boring video otherwise because it handled all the veggie chopping quite easily.


The most it will have to endure is the double handed power chop. Doing banquet work you always need tons of chopped garlic and herbs. This is something I don't attempt with the Watanabe. The Shi.Han passed with flying colors. This was before the chicken and I examined it closely after. No damage.


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## ian (Jul 25, 2019)

I know this isn’t really the point of the thread, but do you spatchcock with a knife most of the time? I find shears very effective, personally.


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## stringer (Jul 25, 2019)

I don't usually spatchcock. But if I did I would use a knife. I have kitchen shears at work and at home but I never use them for cooking. I do break down lots of whole chickens for buffets. We smoke or roast whole birds and then chop them up to put in chafers or carve them at action stations. That involves cutting the spine out as well as splitting reach breast into two pieces with the ribs still attached. That's why I was curious what would happen against the chicken ribs today. For this job at work I use a cheap stainless chef knife, a medium weight Chinese cleaver, or my NOS workhorse carbon Sabatier.


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## stringer (Jul 28, 2019)

I had time to repair the knife today. It gave me a chance to thin it some more. This is going to be a veggie killer. It only needs to be tough enough not to chip on the board. I started with Crystolon coarse. I picked up some interesting items at the flea market this morning. Some kind of really coarse silicon carbide grinding stone. I'm using it to keep the abrasive fresh on my Crystolon.



Next I went to Shapton Glass 500. 



I have bought a few new naturals so after the 500 everything is naturals. Kind of just experimenting and seeing how stuff feels. You get the gist of my strategy from the first two so I sped this one up. At work the knife won't get spoiled like this. Just shapton pro 1000 and then naniwa super stone 2000. But the same mechanics for every knife. They all have matching bevels. Thin a little every time by scrubbing the wide bevel and then finish with a slightly higher angle and target finger pressure on the edge. Every stone use firm but steadily diminishing pressure. Scrub and sweep. Start high on the bevel with medium pressure, finish low near the edge with light pressure. I'll keep thinning gradually until I have issues. And then I will reverse course and thicken the edge until I'm happy with performance. Most knives settle into a weekly touch up routine pretty quick. I believe that if I get the knife set how I like it, maintaining that is actually pretty easy. Compared to never thinning and thinking you'll just get to it someday. That only leads to frustration. Or very expensive professional help. And this way you have very predictable subtly convexed easy to sharpen wide bevels.


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## bm11 (Jul 28, 2019)

Nice vids, I enjoyed them all!


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## MarkC (Jul 30, 2019)

You did a fantastic job with this post and your videos. I will say that I am disheartened to see that just using a knife in a normal setting like you would find in a pro kitchen does such damaged to your knives. Your knife work was excellent and frankly very easy on how you used the board yet all those chips. It makes you wonder if you can really use knives with harder steels in setting like you are demonstrating.


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## labor of love (Jul 30, 2019)

MarkC said:


> You did a fantastic job with this post and your videos. I will say that I am disheartened to see that just using a knife in a normal setting like you would find in a pro kitchen does such damaged to your knives. Your knife work was excellent and frankly very easy on how you used the board yet all those chips. It makes you wonder if you can really use knives with harder steels in setting like you are demonstrating.


Shihan 52100 gyutos are pretty indestructible. Stringers shihan is forming microchips because he removed the sharpening bevel and changed some stuff to it.
If you leave the knife as it is out of the box with original geometry it won’t have these sorts of problems.


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## stringer (Jul 30, 2019)

labor of love said:


> Shihan 52100 gyutos are pretty indestructible. Stringers shihan is forming microchips because he removed the sharpening bevel and changed some stuff to it.
> If you leave the knife as is out of the box with original geometry it won’t have these sorts of problems.



This is true. The factory micro bevel would have lasted me a very long time with no chips and little maintenance. It was just a little conservative for my tastes. I prefer to push the steel to it's limit. See how thin I can take it. And the chips really weren't that bad. I had a hard time even photographing them. Nothing like the damage I did to my Watanabe in the thread below. And that was just off of board contact. But I had done two or three thinning sessions on the already zero ground edge when this happened. Now I have a slightly more conservative bevel on it and I have had no further issues. That's why I got bored and bought the Shi.Han.

https://www.kitchenknifeforums.com/threads/durability-testing-watanabe-pro-gyuto.41263/


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## stringer (Jul 30, 2019)

Double post


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## labor of love (Aug 3, 2019)

My custom shihan 240mm arrived today. Even though I don’t sharpen in the same manner as @stringer does I can understand why he would want to fool around with ootb edge bevel. It’s pretty conservative. 
Really great knife either way. I requested a flatter profile, and Shehan did a great job of creating a good push cutter without deviating too much from what he already does.


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## Barmoley (Aug 3, 2019)

Pictures or it didn't happen


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## labor of love (Aug 3, 2019)




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## Barmoley (Aug 3, 2019)

Now, we are talking. That is very nice.


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## HRC_64 (Aug 3, 2019)

Barmoley said:


> Now, we are talking. That is very nice.



**** ya...that SHi-Han is wicked


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## Simme (Aug 6, 2019)

What a knife looking forward to hear about performance. How much did cost you? ( if this is questions is against forum or what not someone dm me)


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## labor of love (Aug 7, 2019)

@Simme im unsure if you’re asking about my custom shihan or stringers shihan but the answer is the same. Retail $560. He didn’t charge extra for custom profile.


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## AT5760 (Aug 7, 2019)

That is a really nice profile @labor of love!


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## Simme (Aug 7, 2019)

What a great deal/service i really like the profile on yours @labor of love.


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## ian (Aug 9, 2019)

labor of love said:


> @Simme im unsure if you’re asking about my custom shihan or stringers shihan but the answer is the same. Retail $560. He didn’t charge extra for custom profile.



Curious: do many makers take orders for lefty grinds? I'm assuming that it would have been prohibitively expensive or impossible from Shihan. (Thought about writing this on BST, but wanted to keep your thread uncluttered.)


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## labor of love (Aug 9, 2019)

I don’t know what happened...Sheehan himself is left handed..I requested lefty grind...I can return it to him for more thinning if I decide to pull it it from bst


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## labor of love (Aug 9, 2019)

Also, it’s the story of my life. Falling in love with a knife that just can’t cut in an optimum way because I’m a lefty. It’s the number 1 reason why I let go of any knife tbh.


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## ian (Aug 9, 2019)

labor of love said:


> I don’t know what happened...Sheehan himself is left handed..I requested lefty grind...I can return it to him for more thinning if I decide to pull it it from bst



That’s kind of crazy, the choil shots look so right biased. What a drag.


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## labor of love (Aug 9, 2019)

He will work on it some more for me, but I like the workhorse weight at 231grams. Id hate it if he shaved 10-15 grams off it. Id like to just start all over with him on another.


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## panda (Aug 10, 2019)

labor of love said:


> I don’t know what happened...Sheehan himself is left handed..I requested lefty grind...I can return it to him for more thinning if I decide to pull it it from bst


because he likes making money, there is only 1 of you lefties that would even notice a difference..


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## labor of love (Aug 10, 2019)

panda said:


> because he likes making money, there is only 1 of you lefties that would even notice a difference..


Ouch.
I think he just lost track of his notes. The knife is very nicely ground.


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## stringer (Aug 15, 2019)

I've been thinning a little more. About got it where I want it.

I'm making some curry. The way I was taught to make curry, you start with a little onion.


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## stringer (Aug 15, 2019)

I'm going to make several kinds. This mixture will be the base for all of them. Sort of like mirepoix, the Cajun Trinity, soffrito, etc. You saute down your aromatic veggies until heavily caramelized being careful not to burn them.
Onions
Garlic
Ginger
Hot chillies

















I'm making
Daal (lentils)
Ghobi (cauliflower)
Saag (spinach)
Baingan Burta (eggplant)
And Khadi Pekora (Fried veggie dumplings in yogurt curry sauce)


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## stringer (Aug 19, 2019)

Here's a picture of the curries. The cauliflower didn't make it to the second day of leftovers. Left is Khadi, top is daal, right is saag, and bottom is baingan burta.






In regards to the original thread. The Shi.Han it's performing admirably. I still haven't taken it to work yet. I'm a little bit of the wrong kind of busy right now. My knives aren't seeing a whole lot of action. It's given me time to keep thinning and experiment with a variety of finishes. It has a nice zero bevel about halfway up. Then I finish with a micro bevel at about 50 degrees inclusive. This might sound a little nuts but it works very well. I cut the micro bevel with a Rika 5k and then finish it with Hideriyama and then Suita. I think the factory micro bevel was about 75-80 degrees inclusive. That thing would have been extremely durable. Too durable for me. Difficult to maintain. Too hard to thin on stones. Which isn't good in a commercial environment. It was cut deep. Probably done with a paper wheel or something I don't really know. I just know it took a good hour on the crystolon before I could start raising a burr. Now it's quick to reset to zero bevel and seems to have good edge holding and chip resistance. Patina formation is highly manageable. I've left it dirty on purpose several times too little ill effect. Bits of onions and garlic will make brown spots but that's about it. If you wipe it down you're good. No need to be overly cautious about constantly rinsing and drying.







Even with lots of thinning, it leaves very little color or odor on food. Food release is very good. Here's a video chopping some very hard winter rutabaga.



And here's another carrot video. Much less wedging than before. Sorry about the color. Too much light for my phone camera to handle.



And sharpness test after some work on the board


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## Dominick Maone (Dec 30, 2021)

Sorry if this forum despises posting in older threads. Great thread and inspirational cutting skills.

I thought flat grinds were the devil? Or is it “full” flat grinds are the devil? Or do you keep some convexity while thinning?


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## Nemo (Dec 30, 2021)

Many thin knives have a flat (or slightly concave) wide bevel. They prioritise thinness (performance in hard foods) over food release.

Some have a very concave grind but this is difficult (impossible?) to maintain on flat stones, so the wide bevel grind becomes flatter and flatter as the knife is thinned.

Some thinner knives do have a little convexity but IME this is uncommon in thin wide bevels. However, but I have a number of middleweights and workhorses with convex wide bevels and I maintain them as such (I don't flatten the bevel when I thin).


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## stringer (Dec 30, 2021)

Dominick Maone said:


> Sorry if this forum despises posting in older threads. Great thread and inspirational cutting skills.
> 
> I thought flat grinds were the devil? Or is it “full” flat grinds are the devil? Or do you keep some convexity while thinning?



Most of my knives are middle to heavy weights so keeping them pretty convex is easy. But even with lasers a little bit of convexity near the edge goes a long way to help with food release and strengthen the apex a bit.


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## Nemo (Dec 30, 2021)

stringer said:


> Most of my knives are middle to heavy weights so keeping them pretty convex is easy. But even with lasers a little bit of convexity near the edge goes a long way to help with food release and strengthen the apex a bit.


What approach do you use for this?

I seem to recall @Benuser describing gradually lifting the spine from the thinning angle until he creates a burr. Is this the kind of thing that you do?


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## Benuser (Dec 30, 2021)

Nemo said:


> What approach do you use for this?
> 
> I seem to recall @Benuser describing gradually lifting the spine from the thinning angle until he creates a burr. Is this the kind of thing that you do?


IIRC I got the trick from @Dave Martell


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## stringer (Dec 31, 2021)

Nemo said:


> What approach do you use for this?
> 
> I seem to recall @Benuser describing gradually lifting the spine from the thinning angle until he creates a burr. Is this the kind of thing that you do?



Yeah. I think our approaches are very similar. I don't thin knives often. Usually once when I get them and then after that mostly just if there's damage. Like big chips. Basically when I thin I treat all knives like they have a wide bevel shinogi. I erase the old apex down to almost a zero edge where the old microbevel is barely visible. I can raise a burr with a medium synthetic stone like SG2K. Re-establish the micro bevel. Sharpening by hand will have a some natural wobble adding convexity at a very small level. I amplify this by changing my finger pressure and positioning. I start focusing my finger pressure at the top of the "shinogi" and work my way down toward the apex. As I get closer to the apex I steadily increase my pressure and lift the spine a little higher off of the stone. And then I do a microbevel and then finish with high angle passes. The cumulative affect is quite a bit of convexity. I talk a lot about it in the Watanabe thread.






Durability testing Watanabe Pro Gyuto


I usually put a micro bevel on my Watanabe to increase it's durability. I realized this morning after an hour or so of chopping zucchini that I must have forgotten last time I sharpened it. I glanced at the edge and it looked serrated. I decided to go ahead and finish the project I had started...




www.kitchenknifeforums.com





And here's a YouTube video where I discuss my take on convexity.


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## Nemo (Dec 31, 2021)

stringer said:


> Yeah. I think our approaches are very similar. I don't thin knives often. Usually once when I get them and then after that mostly just if there's damage. Like big chips. Basically when I thin I treat all knives like they have a wide bevel shinogi. I erase the old apex down to almost a zero edge where the old microbevel is barely visible. I can raise a burr with a medium synthetic stone like SG2K. Re-establish the micro bevel. Sharpening by hand will have a some natural wobble adding convexity at a very small level. I amplify this by changing my finger pressure and positioning. I start focusing my finger pressure at the top of the "shinogi" and work my way down toward the apex. As I get closer to the apex I steadily increase my pressure and lift the spine a little higher off of the stone. And then I do a microbevel and then finish with high angle passes. The cumulative affect is quite a bit of convexity. I talk a lot about it in the Watanabe thread.
> 
> 
> 
> ...



Interesting video. A bit to think about in there.

Thanks.


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## Dominick Maone (Dec 31, 2021)

Nice video stringer. Gives us all something to think about. I got the impression from this forum that it had to be convex, or an s grind or all food stuck to the knife.

I worked on these two last night. Going to eventually take them down to zero edge with a little convexity under the concave area and see if they perform better. Was a little disappointed in their food release. I guess they were not quite S grinds because there was no convexity near the edge. I added some while thinning. Both are from .09 or .1 thickness stock AEBL at around 62 HRC.


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