Size of edge resulting from sharpening?

[ian]

i meant on knives that looks like in the OP. i have only gotten 1 that was convex (masamoto kuro santoku), 1 almost flat, the rest have been concave.

i have also noticed that 2-3 flatground macs were actually slightly concave. i tried polishing the sides with stones, but i had to resort to sandpaper because of this.

Ah, that makes sense. The knife in the OP is wide bevel, and he was asking about non wide bevel knives.

 

[ian]

I think I understand what OP is asking bc I had the same question. Most knives seem to come with a microbevel edge out of the box. He's asking if he's supposed to stick with that edge, which means you'd be sharpening at a steeper angle right? Based on reading the answers, I guess it's up to the user but at some point you're going to have to thin, so when you thin that microbevel will get "taller" which is fine. Someone can correct me if I'm wrong.

Not quite. Say you have a knife where the primary bevel is 10 degrees and the microbevel is 20 degrees. If you sharpen at 20 degrees (so, hold your knife to the stone so that it makes a 20 degree angle) then unless you do just a few touchup strokes, you’ll quickly abrade off enough metal that the knife with become thicker behind the edge. When you do that, the 20 degree microbevel will appear to be taller, even though it’s the same angle as before. That’s the problem the OP was having. (Although he may have been sharpening at 15 degrees or something instead, therefore changing the angle of the microbevel, but the same thing would happen.)

If you sharpen at 10 degrees instead, though, so laying the primary bevel flat on the stone, then the microbevel will disappear. But you can then just add in another 20 degree microbevel afterwards, and it will look small like before, since the knife is still “10 degrees thin” behind the edge.

 

[inferno]

exactly.

you can put on a very tiny microbevel. the smaller and thinner the better it will cut and the shorter it will last when abusing (chip out).
it will actually cut better even when dull (and in practice "dull" slower) compared to a bigger microbevel, since its the actual geometry that cuts.

 

[Byphy]

Not quite. Say you have a knife where the primary bevel is 10 degrees and the microbevel is 20 degrees. If you sharpen at 20 degrees (so, hold your knife to the stone so that it makes a 20 degree angle) then unless you do just a few touchup strokes, you’ll quickly abrade off enough metal that the knife with become thicker behind the edge. When you do that, the 20 degree microbevel will appear to be taller, even though it’s the same angle as before. That’s the problem the OP was having. (Although he may have been sharpening at 15 degrees or something instead, therefore changing the angle of the microbevel, but the same thing would happen.)

If you sharpen at 10 degrees instead, though, so laying the primary bevel flat on the stone, then the microbevel will disappear. But you can then just add in another 20 degree microbevel afterwards, and it will look small like before, since the knife is still “10 degrees thin” behind the edge.

ohhhhh ok I get that thanks for this

 

[Nemo]

exactly.

you can put on a very tiny microbevel. the smaller and thinner the better it will cut and the shorter it will last when abusing (chip out).
it will actually cut better even when dull (and in practice "dull" slower) compared to a bigger microbevel, since its the actual geometry that cuts.

And indeed this is incorporated in one method of removing the burr.

 

[Isabella Shiri]

OP, you've gotten some great information by people who are both more experienced & knowledgeable in knife maintenance than myself, so I'm not sure I can bring much more to the table. But just to clarify, are we talking specifically about the knife pictured, or about knives in general? From reading your original post, you seem to me to have things backwards. Instead of worrying about the appearance of a knife, it seems to me that it would make more sense to first discuss about how the knife performs the tasks it's used for, and then after that has been ironed out, then worry about the appearance of the knife, and how to address that. If we're discussing the specific knife pictured, what is it going to be used for, a wide variety of tasks, or a smaller number of more specific tasks?

 

[ma_sha1]

Thinning needs comes quite bit later on a properly ground knife. Typically, micro bevel, typically at very high tangle, is needed if the main bevel is at very low angle, 5-10 degrees& fragile. I typically just put on my standard 15 degree angle edge, that should enough for most knives. Please correct me if I am wrong on this.

 

[Mathias Z.]

OP, you've gotten some great information by people who are both more experienced & knowledgeable in knife maintenance than myself, so I'm not sure I can bring much more to the table. But just to clarify, are we talking specifically about the knife pictured, or about knives in general? From reading your original post, you seem to me to have things backwards. Instead of worrying about the appearance of a knife, it seems to me that it would make more sense to first discuss about how the knife performs the tasks it's used for, and then after that has been ironed out, then worry about the appearance of the knife, and how to address that. If we're discussing the specific knife pictured, what is it going to be used for, a wide variety of tasks, or a smaller number of more specific tasks?

Yeah, thanks for all the kind information and answers. To clarify: I would like to know if a small bevel results in a sharper knive (even at the cost of being more delicate) > The knive pictured came in "Honbazuke", with every time sharpening the bevel started to get a little wider. Now I would like to know if this influences the cutting ability by a great margin or if it is so little, that I don´t have to worry about. I get the knife really sharp, but like the way I got it ootb - no way > Same experience with the Tanaka R2, so i just wonder if thinning the knife should always aim for erasing the existing bevel to a Maximum Minimum?

 

[Isabella Shiri]

Yeah, thanks for all the kind information and answers. To clarify: I would like to know if a small bevel results in a sharper knive (even at the cost of being more delicate) > The knive pictured came in "Honbazuke", with every time sharpening the bevel started to get a little wider. Now I would like to know if this influences the cutting ability by a great margin or if it is so little, that I don´t have to worry about. I get the knife really sharp, but like the way I got it ootb - no way > Same experience with the Tanaka R2, so i just wonder if thinning the knife should always aim for erasing the existing bevel to a Maximum Minimum?

Yes, done correctly, a smaller bevel angle will result in greater cutting ability, and as you mentioned, also makes the edge more fragile. FWFI, I also attempt to sharpen at approximately 12 degrees, and just deal with the maintenance. I only thin my knives as they gradually start to wedge when cutting things such as carrots and potatoes. It shouldn’t have to be done every sharpening. As far as the length of the bevel, if you keep the same angle, it will gradually get larger each sharpening, until you thin again. I generally avoid zero grinds where possible, and micro bevels. However, if you’re knife comes with a zero grind, and you want to keep that profile, after, or before any major sharpening, you’ll likely need to thin your knife again. This is where many people use micro bevels to avoid an overly fragile edge.

 

[Mathias Z.]

thanks, thread closed

 

[Benuser]

Normally, I will try to postpone full sharpening of my own knives as long as I can maintain them by touching-up. First with the finest stone, if that doesn't give an immediate result after two light strokes I go to the next coarser one, and so on. Once I need to go back to coarser than 2k it's probably time for a full sharpening. I start with a coarse stone at the lowest possible angle on the dominant side. So, I indeed thin at every full sharpening.
And I will certainly remove any factory edge as soon as possible.

 

[Benuser]

thanks, thread closed

Really?