Are concave grinds are for sales?

[Gooi]

It has occurred to me that my knife will not be as sharp again now that it must be thinned.

I don't think we civilians can achieve a blade as thin once we have to address the year or so of thickening as we don't have a wheel.

Is this acknowledged when we buy these knives that are uber sharp behind the edge? They will be brought down to earth quite early in their life I think.

 

[Jovidah]

There are some knives with concave grinds. My Yoshikane comes to mind. I think a lot of Japanese wide bevel knives are actually slightly concave from the grinding wheels if they didn't flatten the bevel afterwards.
The downside is that it doesn't exactly help food release; convex performs better in that regard.

 

[blokey]

Depends how concave is it, most wide bevel Japanese knife are slightly concave in some regard, usually in the form of low spots, but unless you are polishing them those shouldn’t affect their performance, thinning takes alittle effort but not much more than convex stuff. The other kind of concave is what you see in cutco or Kiwi which are harder to maintain.

 

[riba]

My Dan Prendergast petty is pretty concave. Cuts like a charm though

 

[miggus]

So are there actual advantages to concave bevels?

 

[ian]

So are there actual advantages to concave bevels?

They can be really thin behind the edge, so you can get great food separation. And because of the concavity, they’ll stay thinner over multiple sharpenings than a convex grind knife would. So, they don’t need as much thinning.

I don't think we civilians can achieve a blade as thin once we have to address the year or so of thickening as we don't have a wheel.

If you keep up with it, you can absolutely keep your knife as thin as it was out of the box using bench stones. You won’t be able to preserve the concavity without a wheel or something similar, so you’ll end up slowly converting it into a flat or convex grind, but if you don’t sharpen overly aggressively it’ll take a while for that to happen.

 

[miggus]

Thanks for the explanation!

you’ll end up slowly converting it into a flat or convex grind, but if you don’t sharpen overly aggressively it’ll take a while for that to happen.

Follow-up question: is it necessarily a bad thing if the grind is converted? A steep flat grind is almost as thin behind the edge as a concave one, I'd assume.

 

[ian]

Thanks for the explanation!

Follow-up question: is it necessarily a bad thing if the grind is converted? A steep flat grind is almost as thin behind the edge as a concave one, I'd assume.

No, it’ll just be a different grind. Personally I’d give it some convexity once it really starts to be flat, rather than flat with a bunch of concavity, but it’ll be a while before that happens.

 

[riba]

My thinning plan; hope Dan isn't retired.