Whats the Point?

[Way-Barney]

Hello Guys,

I was in the kitchen draw earlier looking for my chopsticks and found a knife at the back that I bought a good few years ago, The knife proudly claims its hardened to 52-54, so I thought I would give it a whirl on a stone. However when I was checking the bevel grind they are uneven, not in the "this is a mess" way, it looks deliberate.
I am right handed with knives, (left with guns) and the side away from me has a very fine, couple of degrees angle but the nearest side has has about 35-40 angle.

Is there a good reason for this or have they messed up. Its 4 1/2" wharncliffe type paring knife in 420 stainless.

 

[Stuart Davenport Knives]

You might be familiar with 70/30 edges, or 80/20 edges. I have a Masamoto HC petty like that. Basically the total edge angle has one side that is 70%, and the other side is 30%.

In other words, if the total edge angle both sides combined was 10°, one side would be 7° and the other side 3°. Usually the 70% would be on the right hand side of the blade for a right hand user, on the left side for a left hand user.

But the way you're describing the primary grind, hard to tell if it is deliberate or not. Photos might help make a better guess. "Proudly 52-54HRC!" That's a soft one!

 

[Way-Barney]

You might be familiar with 70/30 edges, or 80/20 edges. I have a Masamoto HC petty like that. Basically the total edge angle has one side that is 70%, and the other side is 30%.

In other words, if the total edge angle both sides combined was 10°, one side would be 7° and the other side 3°. Usually the 70% would be on the right hand side of the blade for a right hand user, on the left side for a left hand user.

But the way you're describing the primary grind, hard to tell if it is deliberate or not. Photos might help make a better guess. "Proudly 52-54HRC!" That's a soft one!

Hi Stuart,

I will take some photo's in the morning, its bed time for me here, very interesting that it may be deliberate, what are the advantages in such a design.

 

[Stacy E. Apelt - Bladesmith]

I've seen it on Japanese knives like Stuart noted. I don't know I have seen it on a paring knife, nor do I see any advantage on that size and type knife.
Your description sounds like it was sharpened on a "kitchen knife sharpener" on the back of a can opener.

 

[ea42]

Are you sure it's a kitchen knife and not a grafting knife? Many grafting knife blades are beveled only on one side. Maybe they're using the same concept for peeling.

Eric

 

[Way-Barney]

Photos as promised.
2nd image is the shallow micro bevel side.
3rd is the other side with 1,5-2mm edge.

I know that there is a burr on the edge, just waiting to see if its a re-grind job or if its supposed to be like that,

 

[Stacy E. Apelt - Bladesmith]

Looks like a bad factory grind or bad resharpening. Either way, you can redo the bevels on the flat platen to a near-zero edge and then sharpen the edge evenly.
If it is just for normal kitchen tasks, just resharpen it properly and ignore the bad grinds.

 

[Way-Barney]

Looks like a bad factory grind or bad resharpening. Either way, you can redo the bevels on the flat platen to a near-zero edge and then sharpen the edge evenly.
If it is just for normal kitchen tasks, just resharpen it properly and ignore the bad grinds.

Thanks Stacy,
Rather than waste my time on it, I have decided that I knock up a better one in a couple of hours, I might steal the blade shape though. I quite like that.
I wish my Mrs would look after knives better, she just chucks them in the sink and causes untold edge damage. Blunt to me is razor sharp to her.

 

[Stacy E. Apelt - Bladesmith]

I have a knife block with knives on two sides. The right is knives I use. The left is for the wife. She knows not to use my knives because she will get cut. Her knives are sharpened at much higher angles. I keep hers just sharp enough for her to cut open plastic bags/boxes and cut fruit.

 

[Way-Barney]

I have a knife block with knives on two sides. The right is knives I use. The left is for the wife. She knows not to use my knives because she will get cut. Her knives are sharpened at much higher angles. I keep hers just sharp enough for her to cut open plastic bags/boxes and cut fruit.

I might steal that Idea!

 

[Alex Topfer]

Could be a design for manufacture choice?
That's clearly a knife designed to be made as cheaply as possible, so the grind might be a manufacturing decision?

 

[Way-Barney]

Could be a design for manufacture choice?
That's clearly a knife designed to be made as cheaply as possible, so the grind might be a manufacturing decision?

Hi Alex,
After having slept on it, I have come to a conclusion, that seems logical to me, that the knife had been edge sharpened in an opposing wheel type set up and somehow its been put in skew-whif. Thereby causing the unevenness. If it was a decision to have "odd angles" I think that would be more expensive to accurately manufacture. And as you say, its a cheap throw away knife.