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Randy Griffin

Not trying to re-invent the wheel but...

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Why do kitchen knives have a slight curvature to the edge? Why not make the edge straight. I know there are knives that have a straight edge for special purposes but what is the purpose of the curve in most kitchen knives?

Like I said, not trying to re-invent the knife. Just trying to save myself some time. I want to make a few kitchen knives and I keep thinking of this gyuto style knife with a straight edge. Is this a waste of time? Should I just stick to traditional and move on?

What are your thoughts?

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Posted (edited)

Most slicing operations are made with a light rocking motion so the slight curved edge facilitates the use

Edited by Garry Keown

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Garry has it spot on; a curved edge lets you rock a knife on a cutting board. Additionally, having some curve towards the tip helps with slicing on a board since you can have a tangent contact to the board. Also, an edge which starts out dead straight is liable to become concave with sharpening, which could leave little uncut parts in the food you're trying to chop, especially with vegetables with skins or thin leaves.

 

That being said, there are kitchen knives with essentially straight edges (such as many Japanese nakiri and usuba knives). Their edges are straight because instead of rocking, they are pushed diagonally through food and contacting the board more or less flat.These knives often have a little bit of curve, but they have much straighter edges than western kitchen knives. Hope this helps!

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Slicing or chopping? I consider the rocking motion to be a form of chopping. Slicing to me is back and forth, or, in the case of a very sharp knife, firm pressure strait down. Would a straight edge not work better for that?

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A curved edge means a smaller point of contact.  If you're cutting into a thing, and the edge is straight, then the cut has to break the surface along the whole of the contact surface.  If the edge has even a slight curve, the point of contact is small(er), it takes less pressure to get the cut started, and less to keep it going, since it's shearing rather than just pressing in.

 

One of the the things that I do is a forward moving shearing cut with the last 3 - 4 inches of the blade nearest the handle.  I tilt the handle down and push forward in short, choppy strokes.  I have made (but not finished) a blade that is specifically for that.  It's a tiny little cleaver.  The handle is full sized, but the blade is about 3 x 4.

 

Geoff

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Aiden, we were posting at the same time.

Again, I consider the rocking motion to be a form of chopping. Very well designed for this.

I process venison every year and have always used a chef's knife with the slight curve to slice steak to be cubed.

I have this vision of a similar knife with a straight edge for slicing the muscles into steak. Proper sharpening so as to not get the concave edge is up to the user.

While we're re-designing the knife, -_-, let's make a straight edge with a single bevel.

I guess I'm looking for a knife that will melt through the meat with only the weight of the knife. :ph34r: 

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Posted (edited)
29 minutes ago, Geoff Keyes said:

If the edge has even a slight curve, the point of contact is small(er), it takes less pressure to get the cut started, and less to keep it going, since it's shearing rather than just pressing in.

 

I added another parameter while you were posting. Sharpness, as in the single bevel. That should take care of the pressure needed to get the cut started.

I'd like to see the little cleaver when you finish it.

Edited by Randy Griffin

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19 minutes ago, Randy Griffin said:

Aiden, we were posting at the same time.

Again, I consider the rocking motion to be a form of chopping. Very well designed for this.

I process venison every year and have always used a chef's knife with the slight curve to slice steak to be cubed.

I have this vision of a similar knife with a straight edge for slicing the muscles into steak. Proper sharpening so as to not get the concave edge is up to the user.

If there is a board involved it seems like even a subtle radius towards the tip would be helpful to make sure its easy to get the last little bit of meat against the board. With a perfectly straight edge you would need to either have it come down perfectly to the cutting board all at once or pull the sharp-cornered tip through the whole cut. The second option is certainly doable; exacto-knives and box cutters work like this and make very clean cuts, but they have disposable blades. A sharp cornered tip would work, but would see a disproportionate amount of wear compared to the rest of the edge, and unless the whole edge was sharpened down to keep up with it, would likely naturally become a little round.

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I see your point and agree. The straight edge would need to contact the board in its full length all at once for a perfect cut. Pulling the tip through the cut would never work. And, wear on the tip puts us right back to the curved edge.

I'm going to have to make a straight edge knife and try it. I can't explain it but I think it will make certain cuts better.

I just got a shipment from Aldo so to the drawing board.

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Posted (edited)

This is the knife I made for slicing meat with that very usage in mind Randy. I use it after I have boned out and either steaking or dicing for stews or to further process into ground meat.

To use it there is the slightest curve to the blade with just a touch more toward the tip and I have the tip on the board and slice going forward and drag lightly backward  to reposition for the next forward cut. It has worked as well as I had anticipated it would.IMG_20200105_135936.jpg

 

Edited by Garry Keown
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That's beautiful, Garry.

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My dad was a professional butcher for years, so I got used to the various knives traditionally used for stuff in the western tradition.  For steaks and stew meat, most butchers will use the oddly named "butcher knife" :P that looks like this:

8_2385_26.jpg?1500215500

but for large steaks the scimitar is preferred:

8_2253_26.jpg?1500215500

 

Both of these examples are about ten inches of blade, but scimitars come up to 14 inches of blade.  

 

All that said, if I had to choose I'd pick Garry's.  That's one pretty knife and it has proven it'll do the job.

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Heck, Alan, I'd like to have Garry's knife just to sit and admire!

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1 hour ago, Alan Longmire said:

My dad was a professional butcher for years, so I got used to the various knives traditionally used for stuff in the western tradition.  For steaks and stew meat, most butchers will use the oddly named "butcher knife" :P that looks like this:

8_2385_26.jpg?1500215500

but for large steaks the scimitar is preferred:

8_2253_26.jpg?1500215500

 

Both of these examples are about ten inches of blade, but scimitars come up to 14 inches of blade.  

 

All that said, if I had to choose I'd pick Garry's.  That's one pretty knife and it has proven it'll do the job.

 The only proviso with these two knives is that the end of the handle finger grip projection necessitates its use on the edge of the cutting board or butcher block where I am able to cut anywhere on the block/board the meat happens to be if needed rather than having to shift it to the edge to make a cut.  

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Which is exactly why when someone asks me to critique a design I always point out if the guard drops below the edge.  B)  You'll note I didn't say those specific examples are ideal, the older ones we had in the 70s and 80s did not have that built-in guardlet thingy.  Those were just the first examples of the blade shapes I found.

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Just now, Gerald Boggs said:

So perhaps, lawsuit protection handles :-) 

I was just going to say this... It is such a common thing on production knives it must be related to liability.

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I like that knife Garry. I may play around with a design similar to that. I could never improve on perfection. ;) 

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One thing about knives for use in chopping on a cutting board that I learned from Cris Anderson was that a belly is good for rocking, but it really helps to have a 2 or 3 inches of straight edge right in front of the heel.

 

Cris gave me that feedback on one of my first kitchen knives, and I didn't listen.  I had to go back and tell him he was right a few months later. 

 

What ever happen to him?

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Posted (edited)
45 minutes ago, Brian Dougherty said:

but it really helps to have a 2 or 3 inches 

That's exactly what I do and it works very well. But you'll have to learn and cook yourself to figure out all the why's and how's of a kitchen knife :)

 

This blade is 9.5" long for perspective

 

DSC_1512_edited.jpg

Edited by Joël Mercier

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Joel, thanks for dropping by. I love your knives and that one is no exception. I'm inspired by yours and Garry's knives.

Hard to beat a tried and true design.

I still want to try a knife with a straight edge and single bevel for slicing. How else will I learn the why's and how's.

Beautifull knife btw. Are you forging those with the integral bolster?

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Posted (edited)
1 hour ago, Randy Griffin said:

still want to try a knife with a straight edge and single bevel for slicing

It would work well, but you'll appreciate some belly at tip, or the tip may accidentally get stuck in your piece of meat and damage it. 

 

Thank you for the nice words btw. I am still learning a lot every knife but also got some stuff figured out. Yet, there's a long way to go!

 

And that bolster is in fact sculpted. That's something I like to do every once in a while :).

 

 

Edited by Joël Mercier
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Posted (edited)

Funny story.

Three years ago I made a group of kitchen knives for the annual art show. Every one of them had a slight to moderate belly toward the tip before coming to a straight edge at the heel for a couple of inches. I sold none of them. Everyone who came and handled them said they wanted the edge to be completely straight with no curvature at all. I did manage to trade a 10 inch model for a black jade and turquoise belt buckle, but that's another story. I gave the rest away to family for Xmas gifts.

 

Anyway, the next year I made some 410 SS and 1095 san-mai blades and left the edges perfectly straight from heel to tip. Sold every one of them and one guy bought two of them. One for him and another for his son. Go figure. That same guy showed up last year and told my wife that he wouldn't use the one he kept anymore because there was a small spot where the edge turned a little. He told Liz it was about 1mm out of pure straight. 

 

Last year I made five 1095 kitchen knives with Hamons in the regular style. Small curvature toward the tip. Four of them sold. I kept the small petty.

 

There's a saddle for every butt, and a butt for every saddle.

Edited by Joshua States

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8 hours ago, Alan Longmire said:

Which is exactly why when someone asks me to critique a design I always point out if the guard drops below the edge.  B)  You'll note I didn't say those specific examples are ideal, the older ones we had in the 70s and 80s did not have that built-in guardlet thingy.  Those were just the first examples of the blade shapes I found.

I figured they were just examples of "type" :rolleyes: and not "use this" but like most of us I am inclined to point my understanding of right or what use (or trial and error)  has bought to my attention as being closer to right for a particular cutting/slicing or chopping need.

My father had a set of R F Dick knives from when he had a small goods shop in the 50's and his pair of butcher knives were sort of like that but with a light upsweep to the point on the spine rather than the  bull nose and had a more gentle curve to the tip on the blade edge  and  and of course had wooden handle without the finger guard. I made one like that initially but found the curved end was wasted length as it was not used in the way I was cutting and dicing meat. That was why I made the nearly straight blade and found it to work perfectly for the way I used it.

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