.....

Great question. I don't have the answers for which you are searching, but hopefully someone here will. I'm a bit confused about such matters myself.
--Josh
 
As a very *basic* starting point, if you were to take three pieces of stock and grind them from back right to the front with a hollow, flat and convex grind and then put equal edge bevels on all of them, you would find the knife with the primary hollow grind was the weakest with the lowest shock absorption and the convex the strongest and most durable with the flat ground knife somewhere inbetween.

You would also find that the hollow ground blade would perform by far the best at shallow cutting with the convex ground blade the worst and the flat ground blade again somewhere inbetween. With really deep cutting the performance of the hollow grind will suffer as the shoulders of the bevel can cause binding.

More specifically in regards to really deep cutting on binding materials, chopping for example, the convex bevel will bind the least and the hollow grind the worst. The flat grind will bind somewhere inbetween.

You would also find that as you sharpened each knife the hollow grind would suffer a reduction in cutting ability at the lowest rate and the convex ground blade the fastest. Once again the flat ground blade would see a reduction in cutting ability somewhere in between the hollow and convex ground blades.

The issue gets complicated when the specifications of the grinds change. For example a blade that has a full convex grind (spine to edge) will vastly outcut a hollow ground blade where the hollow grind only goes a little ways up on the blade. As well how the material exerts force on the blade can effect the relative performance.

And of course steel (and heat treatment) also effects the abilities of the grinds. A hollow grind on a very tough steel (1084) could easily produce a much tougher blade than a convex grind on something like CPM-10V. Note also that lots of other things effect the durability (as well as strength, cutting ability etc.) even aspects of the handle can come into play.

In regards to edge bevels, while you could hollow grind an edge it would be very weak as it would have no support. Convex bevels offer a higher cutting ability than flat ground bevels while still maintaining the same level of shallow edge durability. This is similar to double grinding a knife on the Sharpmaker as Joe Talmadge has so often described.

A "zero grind" usually refers to a knife that only has a primary bevel. The knife does not have a secondary or edge bevel and thus the edge is formed with a very low angle. A traditional Japanese kitchen knife for example will have just a single flat grind (ie. chisel) and form an edge that has an *included* angle of about 5-10 degrees.

-Cliff
 
So basically, a flat grind is a good compromise? Say for a general use edc or something, the flat grind would be a good middle ground if you didnt know what kind of chores you were using the knife for? Of course this assumes that all else is equal, which is rarely true.
 
Cliff,
just wanted to say that your explanation was very well done.

Regards, Greg
 
dragon2: yes, a flat grind would be good if you don't know what you'll be cutting!

Byt you always want to go as thin/shallow in your geometry as you can get away with if cutting is important to you. For example, I view folders as very carryable tools for light cutting chores. I use mine for cutting paper, cardboard, food, plastic packaging, tape, string, and the like. So a high hollow ground folder would be good for me. If you think you may have rougher jons, a flat grind, or a saber ground blade (a grind that goes 1/2 or so up the blade, not high like on a Sebenza or a full flat grind) would be good choices.

I like convex edges on my blades. I sharpen using my belt sander and a strop and my edges have never been sharper, nor as durable.
 
dragon2 :

So basically, a flat grind is a good compromise?
Click to expand...

Yes, pretty much exactly.

King Grinch :

http://www.physics.mun.ca/~sstamp/images/grinds.gif

Flat, hollow, convex and overlay to show the difference.

Other terms of interest are :

Chisel grind : which means just one side of the blade is ground. Chisel grinds can be flat, hollow or convex.

Sabre grind : which means the primary grind starts significantly below the spine of the blade. Sabre grinds can be flat, hollow or convex.

-Cliff
 
NEWBIE Overload!!!!!! I think I have been following you, but could you make it a like stupid for me? I apologize in advance but for example what is the standard grind on a production knife like a Microtech, an MOD or even a benchmade? I think that might make it a little clearer for an idiot like me!!!! Thanks guys......wolf:confused:
 
Most production blades are sabre ground (benchmade AFCK), some are not and have full height grinds (Spyderco Military). The primary grinds will be either flat or hollow, the edges are almost always flat ground.

-Cliff
 
Thanks, between the posts and the E-mail, I FINALLY got it....;)
wolf
 
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