Question about Full Convex Edges:

B

blastjv

Joined
Feb 23, 2003
Messages
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I am considering a Bark River Knife & Tool Highland as a General-Purpose/Outdoor/"Survival" knife, teamed up with a Victorinox Trailmaster, a Victorinox SwissTool X, and a Gransfors Bruks Wildlife Hatchet (which also has a convex edge, coincidentally).

I believe I understand the advantages of the Full Convex Edge, but I don't see many DISadvantages. I know that almost everything in life is a compromise, So I guess I have a two-part Question:

1 - What (if any) are the DISADVANTAGES of a Full Convex Edge?

2 - What (if any) tasks would a Full Convex Edge NOT be suited for?


Thanks,

-John


PS - I'd like to hear your opinions about my tool selections, also, but I'm mostly interested in learning more about convex edges.
 
If you ask me, the big limitation of the full convex grind is the overall thickness of the blade. Some types of cuts require a thin blade, although I seldom encounter this in the outdoors. The extra thickness can also add to the weight of the knife, which can be a bit of a downer when you’re on a long hike. Also, a convex grind generally has a larger surface area. This surface area is not an issue when most substrates, but can be a hindrance when cutting flimsy sticky stuff.

The convex grind sounds like a great choice for outdoor work though. I never go hiking without a good convex ground blade.
 
blastjv :

1 - What (if any) are the DISADVANTAGES of a Full Convex Edge?
Click to expand...

The main disadvantage of the lack of a secondary edge bevel is a massive increase in sharpening time. For most convex ground knives this isn't a problem as they are generally used for low wear tasks like cutting or chopping wood. They are also usually on simple steels like 52100 which are easy to machine and thus material can be removed from them easily.

However if you wanted to cut some very abrasive material, which would wear the edge significantly, then having to sharpen an edge which is effectively 1-2" wide can be a large problem. Just consider the huge amount of material which needs to be removed from the knife to move the edge back 0.1 - 0.2 mm, compared to the same honing on a knife with a small secondary edge bevel.

The other area in which performance might be lower is on really low stress cutting. On materials which don't require much strength, a high hollow relief grind makes for a much more effective blades. However this knife can not then do as wide a range of tasks as a flat or convex ground blade.

However what has to be considered here is the nature of the grind. I have a fully convex ground blade from Mel Sorg, 3/32" stock, no secondary edge bevel which will out cut any hollow ground blade I have even handled. However you could hollow it out to make it cut even better. See the knives made by Alvin Johnson for example.

-Cliff
 
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