Martyn
25-01-2004, 01:24
as this drew some interest in the poll, I thought I would expand a little further with a pic....
http://www.britishblades.com/pics/design3.jpg
I mentioned that I thought sharpening a true convex grind was tricky, perhaps the above pic will help explain why. In blade profile A, you can see the purple lines that represent how the convex grind should be sharpened to maintain the grind profile. You can see as the blade is progressively worn away, much of the surface of the blade needs to be worked on, in order to keep the original profile.
On profile B, you can see what I think is a natural tendancy to sharpen only the edge of the convex grind. The net result is a progressively more obtuse blade profile, which has been corrupted away from the original shape.
It's perfectly possible to produce a sharp edge working the knife as in example B, without even realising you're altering the profile (speaking from experience on this point). I think properly sharpening a convex grind is as much an art an making the knife. You cant get jigs for this, so it HAS to be done by hand. Even the hoodoo hone, (which is a good solution) with it's conforming shape, still leaves much for the user to get wrong. Even with a conforming edge, it's perfectly possible to overwork the edge and get that more obtuse profile.
Though I have to confess, I'm probably being a little puritanical about this. In reality, It'd probably take you thousands of sharpenings to change the profile to the extent shown in example B. So long as the knife is sharp after the fact, I dont suppose it matters much. You could always periodically take the whole blade to task and reprofile it, if this became an issue.
I'd love to hear your tips & techniques for getting a good edge on this blade design, as I do believe it's one of the best possible form-factors you can get. I'm tempted to buy into something with a full convex grind (or failing that, make one), but am still cautious about the sharpening difficulties. Opinions?
http://www.britishblades.com/pics/design3.jpg
I mentioned that I thought sharpening a true convex grind was tricky, perhaps the above pic will help explain why. In blade profile A, you can see the purple lines that represent how the convex grind should be sharpened to maintain the grind profile. You can see as the blade is progressively worn away, much of the surface of the blade needs to be worked on, in order to keep the original profile.
On profile B, you can see what I think is a natural tendancy to sharpen only the edge of the convex grind. The net result is a progressively more obtuse blade profile, which has been corrupted away from the original shape.
It's perfectly possible to produce a sharp edge working the knife as in example B, without even realising you're altering the profile (speaking from experience on this point). I think properly sharpening a convex grind is as much an art an making the knife. You cant get jigs for this, so it HAS to be done by hand. Even the hoodoo hone, (which is a good solution) with it's conforming shape, still leaves much for the user to get wrong. Even with a conforming edge, it's perfectly possible to overwork the edge and get that more obtuse profile.
Though I have to confess, I'm probably being a little puritanical about this. In reality, It'd probably take you thousands of sharpenings to change the profile to the extent shown in example B. So long as the knife is sharp after the fact, I dont suppose it matters much. You could always periodically take the whole blade to task and reprofile it, if this became an issue.
I'd love to hear your tips & techniques for getting a good edge on this blade design, as I do believe it's one of the best possible form-factors you can get. I'm tempted to buy into something with a full convex grind (or failing that, make one), but am still cautious about the sharpening difficulties. Opinions?