I thought long and hard before posting again because I neither want to be in nor be seen to be in competition with Chris. But, I think the following, as written, is terrible advice, and didn't want to let it stand without comment.
The best way to maintain angle consistency when sharpening is to forget about "the rules" that say you have to sharpen at a so-and-so angle. The very truth is that most people who sharpen regularly don't even know at what angle they sharpen! Why? The best angle to sharpen at, is to let your handpositions be taken over automatically into a "natural" position without trying to force them into what feels like an unnatural angle dictated by "the rules". Just always obey to what angle your hands go to automatically and you will simply perform the best sharpening ever ànd have less work to resharpen them using the same natural angle.
If Chris means "don't sweat the difference in a narrow range, like that between 14* and 16*, if you can hold one easily and not the other, that's not only true it's good advice. But if he meant that you should sharpen all your knives at whatever angle is most comfortable and "natural," that's bad advice.
Bevel angles can be too acute or too obtuse for a given knife and/or a given task. "Natural angle" notwithstanding, you don't want to sharpen a "lobster cracker" to 10* or a "laser" suji to 25*. There are ways to set your own angles with relative precision, and an excellent way of finding the factory angle on a new knife ("clicking in") which is usually very close to what you want anyway. After sharpening that angle carefully for a little while, your wrist will automatically lock in. Furthermore, whatever angle seems "natural" to you, can and will be altered by minor changes in posture and how you use your shoulders, hands and arms during the sharpening stroke, not mention tempo and pressure.
I'm not saying it's the be all end all of angles, but "clicking in" is usually a very good place to start. Do this by laying the knife flat on your stone, and with a very soft grip, rotate it up so the edge stays on the stone. You'll feel it as you pass the angle the to which the knife was already set. Then, rotate the knife so it goes back flat, and again you'll feel it as you pass the set. Do this a few times, and you'll quickly be able to feel the set itself. Stop rotating at the set, and the knife is "clicked in." For what it's worth, that's how most carpenters sharpen.
Probably the most common method of determining an angle is iterative guesstimation. Hold the knife straight up on the stone and say, "that's 90*." Halve that and call it 45*. Half of 45* is 22.5* (although you'll never hit it that exactly), an excellent and common angle for most older Euro stainless, knives intended for heavy duty work, etc. A third of 45* is 15* -- your basic Japanese knife, while half of 22.5* is a skosh more than 11*, close enough to 10* for high performance Japanese knives. It's not exactly perfect, but more than likely "close enough" for kitchen purposes.
Another method, is to use a protractor and/or graph paper to draw large examples of the desired angle, place a few of them around your stones, and compare frequently as you slowly and gently sharpen. I know it sounds stupid, but it's how I taught myself to profile given angles with fair accuracy. The fact that I am stupid doesn't mean it won't work for you.
Once you've started to sharpen at a given angle, the Magic Marker trick will show you any deviations and allow you to repair them by "sectioning" (working on one part of the edge at a time), and grinding out the low spots. Changes in the width of the bevel shoulder (which you can clearly see against the marker's black) is a very sensitive gauge of angle variation. I can't over-emphasize how helpful the MM trick is, nor how much I wish I'd been taught that way. (I learned from the Boy Scout Manual in the early sixties).
Most of us tend to "click in" unconsciously with just a little extra obtuseness to feel the edge on the stone. Consequently, after each sharpening the angles become increasingly obtuse; and after a few sharpenings we have to "thin" our edges.
As you gain some experience, I think you'll find that motion, posture, pressure and speed are more important to consistency than a "natural" sensation for your wrist. If you sharpen with too much forearm, and not enough shoulder, or too fast or too hard for your skill level, you'll be inconsistent with any angle -- no matter how good it felt.
I suggest taking a look at Chris Ward's sharpening FAQ posted on E-Gullet, who will explain a lot of this. Better still, watch the (free!) sharpening video tutorials at Chef Knives To Go. In addition, you may want to read some of the sharpening posts on my site, CoodFoodGood.
It sounds complicated, but becomes automatic very quickly.
Edited by boar_d_laze - 7/25/11 at 9:59am