@ 07:48 am (GMT)
Andrew MurrayFound this old thread, the link is dead though.
I've got quite a bit of experience in sharpening (as a straight shaver and knife user in general).
From a razor perspective (for straight shaving) having a progression of stones for sharpening is crucial. I usually finish on a natural Thuringian stone which is hard to measure grit size (because it's a natural stone) but is probably the equivalent of around 14k-15k grit. Warrick you may know the brand, it's an Escher, I inherited it, the lucky soul I am.
I start at 1k for my razors on a ceramic Suehiro 1k/3k combination stone (SKG-27 Toishi). It's fantastic. But 1k is somewhat fine for heavy bevel work as may be required on knives. As the razor gets more polished I decrease the grit size for a finer finish until it is literally razor sharp.
There are 2 types of bevels I am aware of, a European style and a Japanese style. The main difference in simplistic terms is that the Japanese style tends to be a single angle bevel all the way down at roughly 25-30 degrees (12-15 degrees each side). Japanese sashimi knives have a single bevel and a flat side for ultra fine cutting and sharpness, as is required for sashimi. The European style bevel is shorter and more stout an angle roughly 40 degrees (20 degrees each side). I think this maybe be what you're referring to as convex blades if I'm reading right...
Either way, the steep the angle, the sharper the knife but the quicker it dulls. A Euro style bevel is preferable for heavy work as Warrick mentioned. I prefer a sharper edge on my kitchen knives, so I prefer to sharpen as demonstrated in the video below. It's by Global brand knives but I'm not in anyway promoting their brand, it's just a good demonstration of how the Japanese will sharpen their knives. Not that I've used the guide rail but I'm sure it's a good idea.
If you ever get the chance I'd highly recommend researching how the Japanese make Katanas and other swords. Absolutely fascinating.
Here is a National Geographic video: https://www.youtube.com/watch?v=VE_4zHNcieM