Grind affects more than sharpenability and cutting performance when dull. It also affects cutting performance when sharp in a wide variety of materials. Hollow grinds, even high hollow grinds, will bind noticeably (for me) in potatoes and apples unless the transition at the shoulder is rounded of flattened. Buck used to do this with their hollow grinds in the 60s and 70s but the norm now is for a clean, sharp shoulder that will bind when slicing. Rounded shoulders on hollow grinds are so uncommon, I have a hard time referring to them as hollow grinds. Better to differentiate them as a (good but rare) variant. In any event, flat grinds outperform hollow grinds, even those with rounded shoulders in slicing tasks, at least for me. I've proven this to myself repeatedly with side by side kitchen work.
This problem you mention is largely a function of blade thickness vs a narrow profile: If you use only 1/4" stock field blades in routine kitchen tasks, on fairly narrow blades, then yes flat ground blades will look very good compared to deep hollow grinds on thick narrow profiles, because you choose tasks and blade stocks that underline the issue... Even taking this into account, I find the issue of secondary grind line "binding" is way, way overblown if the grind line is 2/3rds of the way up the blade or more, and this is even more true in typical outdoor field tasks such as chopping...
I still find the dominant design issues in knife cutting performance are, in order:
1-by far, the primary edge bevel width,
2-then this edge bevel's angle,
3-then the secondary grind line height,
4-then the overall blade thickness,
5-then the primary edge bevel's finish/flatness of its sides,
6-then blade edge profile/overall blade profile shape, and then
seventh, the actual cross-section type used...
Convex edges are an issue of edge cross-section, so that rates above overall blade cross-section.
I also find that a slightly thicker convexed EDGE does much better when working with wood, particularly tasks like making shavings or feather sticks for fire. My conviction is the wider edge on the underside of the cut creates a sliding fulcrum which gives better cutting angle control while the wider edge on the upper side of the cut acts like a cutting wedge, causing the wood to curl nicely.
This could very well be true, but I always wonder how to restore such edges to a highly functional finish... Another observation is that I notice that, generally, convex ground factory blades are ground much thinner at the edge (Fallkniven, Blackjack, some CS), which then makes their sharpness seem attributable to the grind, when the same thinness is achieved on Randalls without any use of convexing (but they seem almost alone in doing this on large fixed blades, hence, despite my not liking their poor uneven finishing standards, and their even poorer symmetry, straightness and surface quality, they are just about the only non-convex large fixed blades I can buy that I know I will not be sharpening for months re-profiling 2 mm thick edges to my usual 20° inclusive...).
I have never understood convex edges, which seems to me an edge design that aims to add blade material exactly where sharpening tries to remove it... Also, convex edges are not easily reproduceable by hand to the standard of finish that makes them effective: Once the factory edge is gone, where to find the shop's slackened grinder? The typical advice for that involves stropping, so in effect just restoring a micro-edge that deceptively shaves, on a steadily worsening geometry... I do note that convex edges are often executed thinner than v edges on large fixed blades, and I suspect this is because the use of a slack belt makes this thinness easier to achieve than on a tight belt (I have no idea if that is actually the case though, or if the extra thinness is a compensation for the blunter geometry)... The idea of convex edges on knives apparently originates with Bill Moran in the 1970s, and I have always viewed this as something that was knifemaker-driven (and enthusiastically accepted by users), rather than something any user would have, in all history, ever considered on his own... It really is a new thing, and I would not call the verdict in, unless some really super undullable steel comes along...
Lastly, on the issue of performance, I don't worry about scratches on my user knives. Not in the least. YMMV.
Looking at most pictures posted here on Bladesforums, I would say scratches are hardly a minor concern for most... Even on a using knife, it is not encouraging to see scratches that are
not use-related, but instead are unnecessary and design-caused, as if the item was poorly thought out and low price...: This means that if you have two identical knives, and want to keep one pristine to admire, while you use the other, even the one you take out of its sheath only to admire will be damaged by just the admiring: It is hardly an indication of high quality if the scratches you see you know correspond to no actual use...
And when comparing a cross-section that promotes unnecessary scratches, moreover curved scratches that swirls, over less scratches that are confined and straight, it is not that small a consideration after the item has had decades of aging added on...
I will concede that some sheaths are soft enough on the inside to avoid this problem on flat ground blades: My father's Sabatier had only very tiny shallow scratches, but the sheath was the typical old-style two-piece leather, whose only protection for the stiching was a few widely spaced rivets: It "hugged" the blade's triangular geometry in a harmless way... It seems common that, as the sheath goes up in quality, which usually means an increase in stiffness, the difficulty in preventing scratches goes up alongside the quality...: My Fallkniven Odin was a using knife, but the massive beige leather sheath made on it such horrible scars, and did them so close to the edge, that, despite a deliberately rougher-grit finish I applied, I had to get rid of it...: This $400 knife just looked like gas station junk... Even Randall's leather is pretty mean on their much-suffering secondary grind lines, and I would shudder to think what would happen without those taking the brunt of the damage... So far, only the old nylon Eagle sheaths of the late 80s early 90s really had a foolproof solution: Rubber inserts with hairy insides: Wonderful...
I think you're using the term "saber ground" in a manner different than I am used to. My understanding is that a sabre grind is similar to a what we often call a scandi grind, as shown in figure 3 in the diagram I posted above.
It could be that a hollow grind would be full height (I guess it would be called a razor or concave grind then), so to me "sabre grind" means anything with a secondary grind line, and is not a specific grind type. It seems most people associate "sabre grind" with a secondary grind line near or below the blade's middle point, and that would imply to me that sabre grinds are all poor and inefficient: It would make it to me a pejorative term, and that is not the intent of a grind type designation...
I read people using "high sabre" and "low sabre", so I use that as well to describe the height of the secondary.
Gaston
