Sharpness vs. Harshness.. you decide
So in the passed year that I've been hanging around these parts, there's been an often discussed topic I've been banging around in my head: sharpness (aka "keeness") vs. harshness. I've been trying to wrap my brain around both of these concepts, and here's my take on it, for better or worse...
My definition of "sharpness": the pressure required to pass the blade through the shaft of hair. The less pressure required to pass the blade through any given hair, the "sharper" the blade is.
My definition of "harshness": How jagged the blade is in relation to how sharp it is. Also the perceived amount of irritation. The more jagged the blade, the more irritation, the "harsher" it is. HOWEVER, harshness is also a product of sharpness. When you start getting really sharp, you're gonna start shaving off more skin and getting more irritation, even if the blade has no jaggies at all (impossible, but we're just talking theory here). So it does follow that harshness (to some degree) advances with every level of sharpness, but can be moderated *greatly* by how non-jagged the blade is for it's current level of sharpness. Did that make sense?
Seperating these two out has aided me a ton in honing. I've read in several recent threads about "how can a blade be too sharp??? You're nuts!" And the relevant responses. I'm on the side of, for the most part, a blade can't be too sharp. Well, that's not *entirely* true... some factory blades are too sharp for me. Anyway, I digress....
Let's hash out the infamous HHT for a sec. There are those that adamantly oppose its use, and an equal number that say it izzle the shizzle. Yesterday I posted that I'm in the HHT fan club, but only a, and I quote, "TRULY PASSED" HHT. Emphasis on the "truly passed" part. It's possible to get a phony HHT result. Overly jagged blades (read: harsh blades) can regularly fool people into thinking they have a passing HHT result. The hair can catch on an imperfection and snap in half. *NORMALLY*, the blade will "ping" or make some such sound when the hair breaks. THIS IS NOT A "TRULY PASSED" HHT RESULT! It is the result of a sharp *and/or jagged* blade. A guy around here used to have an animated .gif in his signature that showed a great example of a truly passed HHT. The hair shaft falls silently and swiftly under nothing more than it's own weight upon contacting the blade. No ping, no pop, no dramatics. It just lays over and dies. THAT is a "truly passed" HHT. A blade so sharp (and so smooth) that the blade passes through the shaft with no more pressure than it's own weight. Awesome. Imgagine how lilttle pressure that same blade is gonna require to pass through the whiskers on your face. And as long as the edge has no jaggies on it, it's gonna be smooth doing it.
So how do you check to make sure your blade is not just sharp but smoooooth? Well, of course there's the shave test. But prior to that, there's a truly positive HHT, as well as microscopic observation. Spend 12 bucks at radio shack on their little microscope. Use it to inspect your bevel/edge very closely. You should see zero chips, and it should shine like a mirror (unless you're using a Japanese finishing stone, then it might look hazy), and you should see *zero* scratches at the very edge of the bevel.
Having a sharp and shiny-smooth bevel/edge = a very sharp, not harsh blade that will pass the shave test with flying colors most of the time.
/rant mode off. :)
