food release

[oivind_dahle]

I prefer convex all the way to the spine

 

[jmforge]

The part where you said that "lower blade convexity" might be a cause for sticking.

I don't know what part of my statement you are referring to or what you are asking exactly.

 

[SpikeC]

As in "less" blade convexity?

 

[Dave Martell]

The closer you get to a full flat grind the more sticking you get (but you also get less resistance - falls through the food better) but the answer isn't as simple as saying convex is better (for pushing food away - release) because convex can very easily be too thick and cause wedging (too much resistance). There's a fine line - a balancing point - between nearly flat with a slight convex and too thick that seems to be the sweet spot - the holy grail - the un-achievable.

 

[JohnnyChance]

The part where you said that "lower blade convexity" might be a cause for sticking.

What part is that? I must not have worded it correctly because that was not what I was trying to convey.

 

[jmforge]

That's because you didn't say it. Salty did. :big grin: so Salty...did you mean a blade that is con vexed too much toward the edge or one that is too flat?

What part is that? I must not have worded it correctly because that was not what I was trying to convey.

 

[Christo711]

I think a minimum in blade surface area is key. I almost prefer slicers with just enough knuckle clearance to rock the knife than tall bulky chef knives. Thinner the better as always, and I agree with Bill about convex grind. The Blazen Slicing Knife I picked up at EE is a great example of the Slicer/Chefs Knife 'hybrid' - do I dare say any kind of indented blade for less stick?

 

[jmforge]

From what I have read on here, I get the impression that Shigefusa knives look like they have been hollow ground, albeit on a wheel the size of a kiddie pool. How do they work as far as stiction goes?

 

[Andrew H]

That's because you didn't say it. Salty did. :big grin: so Salty...did you mean a blade that is con vexed too much toward the edge or one that is too flat?

If you have extreme convexity near the edge your knife will typically be thicker than you want it to be in the mid-section. It's a very hard balance to strike, you want your convex hump to be close to the edge so smaller produce is pushed off the blade by it, but not too low that your knife is thick and wedges.
That's why Shigefusa grinds his knives the way he does. Concave from spine down, then flattens out, then convex near the edge. This type of grind lets the midsection of the knife be thin (less wedging) while you get the some of the benefits of the convex grind.

 

[JohnnyChance]

From what I have read on here, I get the impression that Shigefusa knives look like they have been hollow ground, albeit on a wheel the size of a kiddie pool. How do they work as far as stiction goes?

If you have extreme convexity near the edge your knife will typically be thicker than you want it to be in the mid-section. It's a very hard balance to strike, you want your convex hump to be close to the edge so smaller produce is pushed off the blade by it, but not too low that your knife is thick and wedges.
That's why Shigefusa grinds his knives the way he does. Concave from spine down, then flattens out, then convex near the edge. This type of grind lets the midsection of the knife be thin (less wedging) while you get the some of the benefits of the convex grind.

Yup. Shigefusa, Takeda, Carter, etc. All some variation of the same principle. I find them to release food pretty well, not it is a high priority for me, I enjoy them mostly because they cut well. The finish is also a factor, the rustic finish of Takedas, Carters, etc can also help prevent food from sticking.

You don't have to use a giant grinder wheel either. You could beat that hollow in with a hammer a la Carter and Takeda. Shigefusa clads their knives in a soft carbon steel so they can actually scrape the shape of the blade on the blade face with a sen. It also helps finishing the blade as it is easily to work soft metal than hard metal. I don't know of many makers that have partially hollow ground knives and DON'T use a rustic finish or soft cladding, as I imagine finishing a knife with a hollow grind on part of a hardened blade requires plenty of hand finishing. Other than Shun that is!

 

[jmforge]

If you are hand finishing a blade, the shape of the grind should't make as much difference. You just need to have tools that fit. Trying to do it on machines might be a problem. The issue that I see with thin knives like kitchen cutlery is that you have to do more work after hardening. the good news is there isn't that much steel there to begin with. :biggrin:

Yup. Shigefusa, Takeda, Carter, etc. All some variation of the same principle. I find them to release food pretty well, not it is a high priority for me, I enjoy them mostly because they cut well. The finish is also a factor, the rustic finish of Takedas, Carters, etc can also help prevent food from sticking.

You don't have to use a giant grinder wheel either. You could beat that hollow in with a hammer a la Carter and Takeda. Shigefusa clads their knives in a soft carbon steel so they can actually scrape the shape of the blade on the blade face with a sen. It also helps finishing the blade as it is easily to work soft metal than hard metal. I don't know of many makers that have partially hollow ground knives and DON'T use a rustic finish or soft cladding, as I imagine finishing a knife with a hollow grind on part of a hardened blade requires plenty of hand finishing. Other than Shun that is!

 

[tk59]

I have a knife that is nearly flat ground but the edge bevels are very asymmetric. Food release on this knife is one of the best I've ever tried. Basically, you want the food to have as little contact with the knife face at any one time, as possible. +1 to Dave and his holy grail comment.

 

[JohnnyChance]

If you are hand finishing a blade, the shape of the grind should't make as much difference. You just need to have tools that fit. Trying to do it on machines might be a problem. The issue that I see with thin knives like kitchen cutlery is that you have to do more work after hardening. the good news is there isn't that much steel there to begin with. :biggrin:

Right, if you are hand finishing from start to finish, either grind will take about the same amount of time. If you do some finishing on the grinder then switch to hand, convex or flat grind will take less time.