Originally Posted by
Bart
The wiki article indeed means across, not along.
It was under debate over here, long time ago. There were 2 camps. Sometimes, both camps are right, but in this particular case, I have always felt the "across" camp was wrong. (They were a minority, but some senior members adhered to it).
I don't think if you go very gingerly across, that you will do much damage to the edge, but still you wont be able the estimate the sharpness as precisely as you should for razor use. Moving along, things like micro-shipping can easily be felt.
Across is to probe for the kind of sharpness you expect to find on a well honed kitchen knife. If it grabs it will still perform very well processing vegetables. But it won't necessarily shave.
Along is to discern differences in shaving sharpness. Barbers used it to check if a razor was sufficiently stropped. With some practice it is possible to feel the level of sharpness starting at the level a blade starts to shave soft arm hairs till all the way up to the point where it will shave hard beard hairs without pulling.
I have always felt the wiki article should be adjusted, but without any real consensus, who am I to do so?
Bart.