Kitchen knife design critic please.

S

skillgannon

Joined
Apr 27, 2009
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Can those of you who know about kitchen knifes give me a little help with checking my blade design. These are in different stages of being done I know. Also I am still working on fit and finish with handles. I'm mostly concerned with blade profiles and handle angles. The 2 in the center I am trying for a S grind( or at least what I think the S grind is. If that's Salims thing and I am using it I'm sorry. But still a huge fan.) I'm struggling with the high getting rhe high hollow right. Any other points are welcome.
 
I can't speak to the s grind. I like the profiles, but the one on the left I would prefer that there be more relief in front of the scales. I like to choke up on a kitchen knife.
 
I'm talking about how you have the curved radius in front of the handle, edge side. As opposed to the straight 45° angle
 
Don't forget one of the most important parts of a knife, the edge. Especially on kitchen knives you need to make conscious decisions on this matter.

For example, how much of a flat spot do you want? There are of course different schools and taste (much dependent of the kind of kitchen knife in question). Even if you don't decide on anything fancy you at least need to make a decision and stick to it. Otherwise it's easy to "just get the edge you got". Also make sure that you've got no "holes" in the edge.

I'm a big fan of large enough flat spots, to really cut through the vegetables.

Your no 2 from the left seem to have some issues with the edge curve.
 
I agree about the cutting edge. It looks wonky on the 2nd one.

On the first one, what's going on with the pin going right through the middle of the handle spacer and part of the main scale and the bolster at the same time? Seems like it's missing the point of having a pin at all, since they're primarily to resist shear.

I like the 3rd knife, but I would recommend having the edge straighten out toward the back, just like currenthill mentioned.

My only concern on the 4th one is knuckle clearance.
 
General blade shapes look OK.

I am not a fan of pointed butt kitchen knives like #1 and #4.

The misplaced pin on the left knife handle is very off-putting. It should not be on the bolster joint. I would have moved it back about 3/8".
 
I got into making knives because of cooking and discovering Japanese kitchen knives then custom knives by western makers. There is a huge variance in techniques used by people in the kitchen as well as physical differences in end users.

A person that chokes up on the handle and uses a pinch grip (holds the blade between the pointer finger and thumb) can tolerate a bit more angle on the handle than somebody who uses a hammer grip. This is exacerbated when the knife is rocked from the tip to the heel on a cutting board (higher angle handle is awkwardly high at the start of the rocking motion). A high angle may also tend to be worse for a short person who is closer to the kitchen counter versus a tall person. A slicer needs less knuckle clearance than a chopper. And so on...

The edge profile of where, and how much curve/belly and flat spot can also be optimized for the technique of the end user. Somebody who chops most everything with a mostly straight up and down motion needs more flat spot than somebody who rocks the knife.

A rocking motion with the tip on the board has more leverage than a chopping motion up and down. In my opinion the rocking knife's optimal balance point is further back towards the top of the handle whereas a chopper needs more blade forward balance for the weight of the blade to help to chop through. The rocking knife with more belly can be left with a little more behind the edge in my opinion, but I think grind to zero (or almost) before sharpening works best on chef's knives.

Also, if you do a profile mock up in cardboard or wood, you can test how it interacts with the cutting board which helps tweak the design. I also check the knife at the point it's profiled as well as after the post-HT grind to make adjustments if it's not interacting the way I intended.

Having said that, you can make knives that work for the average user. I would say study the features and differences between popular German, French, and Japanese kitchen cutlery. For brand examples look to German: Wusthof, Henckels; French: Sabatier; Japanese: Hattori, Masamoto. There is a reason they are popular. There isn't too much innovation left to discover in kitchen knife profile and geometry in my opinion but like any kind of knifemaking it's still a challenge to make the best knife you can.
 
currenthill said:
Don't forget one of the most important parts of a knife, the edge. Especially on kitchen knives you need to make conscious decisions on this matter.

For example, how much of a flat spot do you want? There are of course different schools and taste (much dependent of the kind of kitchen knife in question). Even if you don't decide on anything fancy you at least need to make a decision and stick to it. Otherwise it's easy to "just get the edge you got". Also make sure that you've got no "holes" in the edge.

I'm a big fan of large enough flat spots, to really cut through the vegetables.

Your no 2 from the left seem to have some issues with the edge curve.
Click to expand...

That one still needs a lot of work. How long should the flat spot be? Is there a reason for different preferences?
 
milkbaby said:
I got into making knives because of cooking and discovering Japanese kitchen knives then custom knives by western makers. There is a huge variance in techniques used by people in the kitchen as well as physical differences in end users.

A person that chokes up on the handle and uses a pinch grip (holds the blade between the pointer finger and thumb) can tolerate a bit more angle on the handle than somebody who uses a hammer grip. This is exacerbated when the knife is rocked from the tip to the heel on a cutting board (higher angle handle is awkwardly high at the start of the rocking motion). A high angle may also tend to be worse for a short person who is closer to the kitchen counter versus a tall person. A slicer needs less knuckle clearance than a chopper. And so on...

The edge profile of where, and how much curve/belly and flat spot can also be optimized for the technique of the end user. Somebody who chops most everything with a mostly straight up and down motion needs more flat spot than somebody who rocks the knife.

A rocking motion with the tip on the board has more leverage than a chopping motion up and down. In my opinion the rocking knife's optimal balance point is further back towards the top of the handle whereas a chopper needs more blade forward balance for the weight of the blade to help to chop through. The rocking knife with more belly can be left with a little more behind the edge in my opinion, but I think grind to zero (or almost) before sharpening works best on chef's knives.

Also, if you do a profile mock up in cardboard or wood, you can test how it interacts with the cutting board which helps tweak the design. I also check the knife at the point it's profiled as well as after the post-HT grind to make adjustments if it's not interacting the way I intended.

Having said that, you can make knives that work for the average user. I would say study the features and differences between popular German, French, and Japanese kitchen cutlery. For brand examples look to German: Wusthof, Henckels; French: Sabatier; Japanese: Hattori, Masamoto. There is a reason they are popular. There isn't too much innovation left to discover in kitchen knife profile and geometry in my opinion but like any kind of knifemaking it's still a challenge to make the best knife you can.
Click to expand...

SPOT ON
 
Stacy E. Apelt - Bladesmith said:
General blade shapes look OK.

I am not a fan of pointed butt kitchen knives like #1 and #4.



The misplaced pin on the left knife handle is very off-putting. It should not be on the bolster joint. I would have moved it back about 3/8".
Click to expand...

Is there a reason that you don't care for the pointed handles or is it something with the lines that looks bad?

Like I said the fit and finish on these is not perfect. That Corby bolt drives me nuts every time I look at it. Since I am making test blades I'm not worrying as much about it. I'm trying as many techniques as possible and a few eggs are getting broke:oops:.

The Wa handled knife I chased the high hollow to much and and it has a few problems. I think my heat treatment might be off as well.
 
Milkbaby I reread your post. If I am reading it right does it mean that for a rocker type blade the handle might slope down somewhat rather than angle up?
 
"...Is there a reason that you don't care for the pointed handles or is it something with the lines that looks bad?..."

Yes, it will rub and poke your hand in use. This is often called, "hot in the hand".
 
skillgannon said:
Milkbaby I reread your post. If I am reading it right does it mean that for a rocker type blade the handle might slope down somewhat rather than angle up?
Click to expand...

In my opinion it should not angle up as much because in use the whole knife is angled up prior to rocking down for the cut. Also need to balance between angle and knuckle clearance too. It's worthwhile to go a bit taller at the heel to get knuckle clearance.

Murray Carter's book 101 Knife Designs is pretty awesome as far as principles of design and practical steps on developing your own. If you start from there and use your own and friends user experiences, I think that goes a long way.
 
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