210mm gyuto critique please

timos-

timos-

Knifemaker / Craftsman / Service Provider
Joined
Oct 22, 2012
Messages
2,164
This is not my first attempt at grinding a gyuto but it is the first one I have "finished".
Back in the day I was attending a design class and the Prof. nearly failed me on a project. I had 4 different boxes filled with different textures and smells. One box was filled with pennies and one penny in particular had a small hole drilled through it. He immediately saw it and said it was inexcusable and he would have given me a perfect grade if it was not for that one aprticular penny so he gave me a D- instead. I think he was trying to teach me a lesson and I think I may still have not learned this lesson. In any case this piece represents my finest work thus far. Please comment and criticize as this knife is meant to be both good looking and functional. The particular duty it is to excel at is a pinch grip cutting boneless chicken (customer request).
Specs:
210 mm blade length
Handle Construction is essentially hidden tang.
Bog Oak Frame and bolsters.
Amboyna Burl dovetailed scales.
Mosaic Pin and brass spacer.
West systems Marine Epoxy was used to join the woods and seal the tang.
The Mosaic Pin holds the entire thing together the glue just seals everything out.
orig.jpg
 
nice....i myself like a little more indent at heal so finger rides more inline with top..like a qtr cirlcle at heel under handle....the tip is right on for me...jeff
 
Thanks for input rc4u12.

I forgot to include a heel shot
11000649_736579779788785_1387624897_o.jpg
 
I think you did a great job :)

I like the profile. I dont know about the geometry or if its blade heavy or handle heavy.
Dont know about the edge either :P

The handel looks good. All in all I think you did a great job. Congrats

(Makers mark should be put on it)
 
It balances about a finger's width in front of the bolster. The edge itself is .010 behind the edge. Duratech 20-cv is very tough steel to work after heat treat. I wanted to keep the hand sanding parallel with the edge so was unable to really get it down to a real laser. Its ok though next time I will try .005 behind the edge going into heat treat, either that or a belt finish. Ahh makers mark, i know I need to mark it tonight actually , would you believe I forgot to do it before I headed to the ECCKS show this past weekend.
 
From what I can see I have nothing critical to say. Great looking profile and handle. 0.010 to 0.005 on the edge makes it really nice.
 
Brad at Peters told me M390, which is the same composition as 20CV, and S35VN should be about .010 minimum before heat treat. IMHO, about .005 behind the edge after HT would be about right. I've been thinking about trying 20CV since M390 is so hard to get. How do you like it other than being a bitch to sand after HT?

Tim
 
It was really not too bad to grind, just costly. This blade required two fresh 80 grit Blaze belts to rough the bevels and then some gator belts to even up and finish. I tried to pull off a 400 grit hand finish. When I was sanding after heat treat there were deeper scratched than I realized and I could not for the life of me get them out. I never actually touched the blade with a belt after heat treat except for the tip area near the spine. I am going to use this steel as a more wear resistant alternative to aeb-l as long as it is available.
 
The bevels are a shallow 36" radius hollow grind. It is very nearly flat. The bevel was only about 2/3 as high as the knife at the heel. The idea was to keep the blade a bit more blade heavy and balanced than a FFG would allow. I washed out the grind line when hand sanding so I could blend it all together like you would see on a FFG. This also allows the edge to be convexed more easily. I believe other kitchen knife grinders refer to it as an "S" grind?
 
I asked about the grind because it is important for food release. Have you tested thin slicing stuff(zucchini, tomatoes, cucumbers), chopping onions /cabbage, as well cutting root veggies (potatoes, carrots, squash)?

I like the shape a lot and the handle looks very nice.
 
mainaman, good questions. Food release has become the hardest aspect of kitchen knife design for me to decipher. So far I have not been able to find out what exactly is the best grinds to negate food sticking. I did not test this blade myself, I sent to customer before handle was installed to ensure they were happy with it. Another blade of mine I have in the kitchen is ground in a similar way and I had a slice of potato stick to it almost like it was glued there. CRazzy. With cucumbers and onions it wasnt so bad. Then I read that it is mostly technique to avoid sticking...So i was able to with a little practice slice away with no sticking at all. However, I am a snail in the kitchen compared to a pro on a line. Ahh it is all so subjective, but also why i think chef knives are the ultimate custom knife challenge.
 
I consider western style Japanese kitchen knives the best tools for cutting foods. They are convex ground, never hollow, that is why I asked because Japanese are very rooted in tradition and who knows there may be other grinds that work just as well but not popular. I have experience with convex and flat grinds, and convex grind when done right has negligible stick to it. Very thin sliced potatoes will stick to any knife IMHO, but for that application there is a mandolin. So for food prep in kitchen (pro or home), well done convex works fine.

During the years there has been an evolution of sorts on the thickness of knives. 3-4 years a go people really got into very thin knives with light convex, and asymmetric edges grinds. The theory was that thinness equals easier cutting, but that turned out to not be quite true because there were issues with cutting root veggies. Then some knives were imported with thicker stock and well done convex which outperformed the thinner counterparts. My observation, from others accounts and also my experience with a variety of kitchen knives is, that thicker stock with a bit more convex works better. The trick is to not have too thick of a stock because then the knife will start to wedge, basically splitting the food like batoning.

I do not know if you are familiar with Kitchen Knife forums, but there you can read a lot of discussion of those issues, many knife makers post their work there. I think it is a good resource for kitchen knife making.
 
As far as I understand even with a convexed edge there is still a considerable portion of the blade that is flat creating a more surface to stick to. My theory was to create slight hollow bevels to enable food release by reducing surface area it could stick too as well as enabling ease of sharpening and thinning over time. In the end though each and every user has their own experience. I think that is the beauty of a custom kitchen knife. It can be made exactly to the needs of the user.
 
I have had guytos that have full height convex, Shigefusa and Kato to be more exact. The Kato especially was extremely good at food release, the best of what I have experienced with kitchen cutlery.
As you say if the customer likes the knife that is what matters.
 
mainaman i think you have inspired me to try a full height convex...I have a heat treated unground blank of 170mm blade petty in aeb-l, the trick will by symmetry with only an eye for reference :)
 
This knife is looking great! I specialli liked the way you built its handle.
Cool picture, too.
 
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