Why the grooves?

Jason B.

Knifemaker / Craftsman / Service Provider
Joined
Jun 13, 2007
Messages
11,162
Do the grooves in the blade do anything, do they make it harder to cut?
 
Actually make it easier to cut certain things, like cheese for one. This was something RJ Martin, the designer, did on his custom blades.
 
Hi guys: Sorry not to have responded to this thread earlier-I have been at the New York Custom Knife Show since Thursday.

I get a lot of questions from people who are concerned about what will happen to the grooves of the knife as it is resharpened. The answer is "ABSOLUTELY NOTHING!".
You can sharpen the blade until there is pretty much nothing left of it, and the only thing that you will see is that the edge bevel will become a bit wider. This is because the edge will become thicker as more and more of the blade is removed from repeated sharpenings. This is the same thing that would happen to any flat ground blade. It will still get sharp, and it will still cut like crazy.

The grooves will always disappear as they meet the edge, just the way they do when the knife is new. So, no need to worry! Sharpen away and enjoy the unique look of the blade!

As to cutting performance, the same general principles apply to the striated or grooved blade as to any regular knife-the cutting performance is directly related to edge sharpness and edge thickness. The standard groove, being flat "ground" will have a slightly thicker (and more robust!) edge than a hollow ground knife.

In cutting soft materials that don't bind when cut, you won't see any difference between a grooved blade and a blade without grooves.

In cutting harder materials like rubber hose, plastic tubing, etc., the grooves actually improve cutting performance because they cut the friction by about 80%. This is because the material being cut is only rubbing on the tops of the ridges!

When I received my first batch of Grooves from Kershaw, I immediately passed them out to my friends with the instructions "Beat the he** out of them". One went to an Electrician, one to a telephone company lineman, one to a powerplant maintenance supervisor, and one to an FBI agent. All of them have been impressed with the edge holding of the steel and the durability of the edge.
One report involved opening cardboard boxes for 2 weeks, at which time the knife was handed to an employee who had a farm. He opened 59 burlap seed bags, shaved wood, and performed other farm related chores. This guy also built houses for hurricane victims. He cut sheetrock for an entire weekend, which was a good verification that the grooves don't impede cutting performance. After all this, my friend restored the knife to shaving sharpness in less than 3 minutes (measured time!) using a ceramic rod sharpener. I'd say that ranks as exceptional performance from a factory knife!

Please keep those questions coming-I'll be here to answer them for you!

BTW, the new, striated Tanto Groove from Kershaw will feature a hollow "ground" blade. This knife promises to really push cutting performance to new levels!

Stay Sharp,

RJ Martin
Groove Designer


They do have a purpose. I love my tanto groove and orange zing--in fact, I have them both on me.
 
On my Zing and my groove they seem to help cutting most things. I like them and they look cool.
 
Well, looks like a orange Zing is in my future. :D
 
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