Convex blade grind

made2cut

made2cut

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Dec 4, 2001
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I have quite a few knives with flat and hollow gound blades but only two with convex and both of those are Marbles. Are convex grinds much more difficult to produce? Can anyone let me know some makers other than Marbles who do this type of grind?
 
My only knives with convex grinds are Marbles and my CS SRK, which ended up with a convex edge after I hand-worked the original edge over with a file. I believe convex grinds are more difficult to create, and you need a slack belt to do it on a commercial basis, which can be quite tricky. The only other manufacturer that I klnow of that applies convex grinds is Cold Steel, and only on its stainless Trailmasters.
 
Blackjack knives also have a convex grind. Not only is the convex grind easier to sharpen, it seems to be a quite a bit tougher as well.
 
Thanks for the replies. I can't see how you can get a tougher edge just by the nature of the grind. It seems that changing directions while cutting is easier too.

Any custom makers out there doing this grind?
 
I just finished a drop point utility/hunter. I started with a flat grind and was trying to do the finishing grind after heat treat. Didn't have any good grinding belts left :( so I made it a slightly convex grind in order to have less time at the grinder (less material to remove)and less chance of overheating the blade.
It was hard to get the edge just right and get a nice rounded bevel.I wouldn't say that its any harder than a flat grind or hollow grind though. Its actually more forgiving, as theres no flats or bevels to get even. It has to be symmetrical but you can cheat a little, since its harder for someone to look at it and catch your mistake.
I think the reason production companies don't use it more is that its not something that works well with their normal production. The blade has to be rotated back and forth alot to get a good job. With a flat or hollow grind a machine can hold it at the right angle to the grinding wheel/platen and get good results with very little motion, and only have to move back and forth for the most part.

They are tough and cut very well though.
 
convex primarly benefits chopping blade liek axes head, no? Convex primary edge is useful for any blade but for slicing, I believe flat grind is more efficient.
Of course with slight convex, it is of little consequence, but with more pronounced convex it matters like on khukris.

Regards

Martin
 
I'll knives shalt have convex grinds!!! This is the word of Buzz.
 
I apply a convex edge to the knives that I make. A full flat grind with a convex edge cuts like a dream. Convex efges seem to really bite and part the material you are slicing. Sweet.
 
The main reason that convex grinds are not popular is that they cannot easily be maintained by the use of v-type systems like the Sharpmaker or clamp and jig systems like the Edge Pro. They require freehand work on some kind of slack medium, or a lot of skill and a flat hone.

Note there is a huge difference in the performance of a knife with a dual convex taper, one with a full convex taper, one with sabre convex grind (with and without a secondary edge bevel), and simply a knife which just a convex edge bevel (with a flat, hollow or convex primary grind). All of these have convex bevels of a sort, but they are radically different knives and thus should not be quickly lumped into one group.

Specifically, the dual convex grind gives very high cutting performance over a wide range of tasks, the highest flexibility and impact resistance, and maintains its cutting ability with extended sharpening. A sabre-convex ground blade with a secondary edge bevel has a low cutting ability in comparison and the edge thickens rapidly with extended sharpening.


-Cliff
 
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