So I just reground my itinomon

which intinomonn is that?

 

It's the old 210 nashiji model. Big belly originally.

 

Way nice, Cris did a KILLER job!!!

 

I can see both? Maybe he quoted it out of my PM's...so I can see it but you all can't.

Trust me, I could make a light saber look bad in the kitchen, lol. Put me in front of a camera and it gets slightly worse .

This I'm working on!!

The original knife.

Thanks Al!! I hate to have taken over bieniek's thread lol. I watched his video again, and can see some very subtle differences in the way the knives were modified. It looks like he kept the shorter shinogi height (and thus a thicker knife at the shinogi) towards the heel. I actually thought about this after the fact, as it probably wouldn't affect performance much, and would aid in increasing anti-stiction in that area vs the grind I did. It's a lot easier to remove metal than put it back on though, so it was kind of a moot point by then . Regardless though, the hollow forged into the blade flats makes for great anti-stiction regardless, so the thinner shinogi wasn't a complete loss.

I'm curious though bieniek...did you leave it shorter on purpose for the reasons I mentioned? Or was it a factor of doing it by hand? On my grinder taking off that metal to even out the blade road takes just a few passes, by hand it'd take hours lol.

 

Dont worry about the thread Cris. The stress lever is at zero

Before I start answering on the grind thing, let me first ask you this: are you insanely insane?? You really think I did that by hand!!?? ump
?!?!
As early as 3 years ago I was demolishing this blade with a belt sander hahaha, in that time some innocent 10 mills off the height were sanded to oblivion.
I grind everything on a belt...My kato was, some expensive yanagis, basically everything that needs thinning.

Now, with that out of the way:
1 Some time ago, when the blade started loosing its, otherwise very durable, black finish, I polished the blade [machine job] thinning somewhat the sides, so that is a part of the reason why "shinogi" seems lower.
2 One other thing worth noting is that in the video you can primarily see the right side of the blade, the left side [for a righty] is ground at even more obtuse an angle then the right side= shinogi is a tad closer to the edge still.

Why is that? Just my philosophy.
I believe that the right hand side should have a mildest curve to it, convex from the shinogi all the way to the edge.
Entirely different on the left hand side, where I look for a bulky differing between blade flat and a shinogi and a secondary bevel.
I believe this, by some natural force, when slicing/chopping fast, makes the knife un-stick
[you are familiar with those laser type knives with flat grind on one side that when it gets stuck to a potato, you need 10 tons garage press to release it?]
itself from the produce on its left side and held by cutters left hand. At the same time, just the gentliest of curves on the other side makes the produce let itself cut easier without too much of a drama and just slide off of the concave secondary bevel.
My sharpening angle on the right side is also steeper.
It might be a load of crap to you, guess this to me is what his kiai is to Master Motorcycle driver Murray Carter :k

3 To answer what youre asking about finally. I would not say higher shinogi means thinner. My first thought was that the blade must have been thicker at the heel??
But no, you sneaky man...

If it would be so, I would not care about how funky this or any other shinogi looks like on that cheap of a knife.

 

Ahhh! Good to know!! I was saddened by the idea of you slaving away on a stone or diamond plate for years to work on that knife .

More seriously though...I knew that lol...I'd just completely forgotten!!

On how you ground it, not crap at all!!...and I think I've got it. The right is a convex (helps with food separation without sacrificing cutting too much). The left I might not be understanding completely. The blade road is basically flat?...with a sharper angle from the shinogi to the primary bevel.

If I've got that right, it makes sense. Sort of like a cross between the laserish one sided flat grind you were talking about, and a more typical double bevel. The angled, flat blade road on the left sort of pushes the knife from the product, limiting suction, while the gentle convex on the left separates the product. The result (when used quickly as you stated) is a knife that steers cleanly, cuts well due to reasonable thinness, and is virtually suction free on the left, and stiction free on the right.

I tend to try to think of all of this in terms of physics. Thinner blades penetrate the product more easily, yet the less physical contact the blade can make reduces stiction. These two facts tend to oppose each other in practice on a knife...so we end up with things like convexity and short blade roads and other patches to make it work. Add in things like right or left handedness, cutting technique (or in my case, lack of lol), what kind of product the blade is intended to cut, and it's all a compromise. A double hollow ground Forgecraft for example, cuts great due to the inherent thinness of the grind...and the break in geometry at the top of the bevel knocks the food off the blade (along with the air breaks the pattern provides) for wonderful anti-stiction...but the knife is difficult to maintain the thin edge after time, due to the nature of the geometry...and many people simply grind it flat so it can be kept up.

In the end, I can talk geometry all day long lol. It's as fascinating to me as metallurgy to be honest.

 

My brain hurts!!! ump

 

Would that be looking from the heel? Or from the tip? The way I pictured from your description, the knife would be pointed towards us in your picture, making the left side of the picture the right side of the grind. Your picture is pretty much exactly what I was thinking though. A difficult grind...but I could see it being very effective. I'd be curious what kind of measurements you've found most effective. Most of my knives are symmetrical, with the shinogi being around 2cm above the edge depending on the knife. I do a blended shinogi as well, no sharp delineation. There is also the slightest convex at the edge. To give you an idea the thicknesses...I'm usually around .6mm-.7mm at 1cm above the edge, and between 1mm-1.4mm 2cm above the edge (depending on the purpose of the knife). This tends to taper in from about 1cm in front of the heel, to the tip.

 

Awesome work Cris

 

Pictured is the heel of a exemplary grind. The blade is not pointed towards us. The left side on the picture represents left side of the blade.

Yeah I know.

As to the measurements, I just thin it until I feel happy about it. Dont even have a tool needed. What I noticed though is that if you just finished thinning, and the primary bevel is wider than lets say .5mm you got it wrong lol.

 

I see! So basically it's a double bevel knife with an exaggerated single bevel uraoshi type grind, with everything smoothed lol. Makes sense, and I can't see any reason why it wouldn't work perfectly. The right side bevel would push food off cleanly, and the left side hollow would eliminate suction stiction. It would still steer perfectly straight without issue as the edge is mostly centered, and any small corrections necessary could be made up in sharpening.

I can see where you might have caught some crap for this in some circles maybe...but honestly it makes perfect sense.

My grinds would be a cross of both your left and right grind, but symmetrical. If you took the lower portion of the right hand grind, and the upper portion of the left hand grind, you've got it.

On the thinning thing, I keep numbers so I don't have to cut food all day to see if each knife is right . That said, I agree completely on how tall the primary bevel should be. I grind/polish my knives to a zero edge...sub .05mm, run it about 5 passes on a coarse DMT plate edge down to remove any weakened steel...then put my edge on from there.

 

And I could listen all day!
Enjoying this discussion

 

You have to cut the food all day. That is where the practice comes from But honestly, how many veg you have to cut to get the feeling?? Apart from the feeling that comes from experience??

The hollow you talk about does not need to be there at all. It might be flat what is the main thing about it is that the angles of attack are different on both sides on secondary bevels.

 

That's really interesting! I may have to grind something up like that (much thinner of course, lol), and try it out!! I still like the idea of the hollow there though. I think it would very much aid in reducing suction stiction.