Can't say it any better than this: http://straightrazorplace.com/srpwiki/index.php/Hanging_Hair_Test,_from_trick_to_probing_method
Hmmmmm Ok here are some unfortunate truths.. All these tests need to be calibrated The shave test is honestly the only test that really matters Now the TNT / Thumbnail Test is designed to check for a positive bevel set, it will harm a fine shaving edge so when you did that, even if the razor was "Shave Ready" and could have passed the HHT is won't after the TNT you dulled the blade.. The good news is that a True Shave Ready edge usually is too fine to pass a TNT very well, it just doesn't have the "Bite" to do so.. This means that the edge probably wasn't sharp enough to shave anyway before you tested it.. The fact that your HHT failed with a DE blade also tells me that the random hair was a bad idea anyway, you have to take the time to calibrate that test and then alwasy use it the same way at the same time with the same person's hair, otherwise it is useless.. Here is what I use when honing, it is just a guide you have to figure out what works for you.. Bevel setting TNT Armhair test Magnification Sharpening / Polishing TPT / Thumbpad test Armhair test and it's variations Finishing I use the shave test, I have a very well calibrated HHT but I just really don't use it any longer, except at the Meets to show off hehehe
I don't bother. I really believe it's all about the bevel, then polishing it (if that's the right word). I think Glens approach above is pretty logical. Personally, I just pop some hairs off the back of my hand to gauge how sharp it is. If my blade isn't sharp, it's just about a guarantee I don't have a correct bevel. Now, If I'd have used my magnification (60x loupe) I would have known about the bevel before my first shave but I'm pretty casual about it. I'll get it right for tomorrows shave. Experience is a good teacher. I'm not discriminating enough to tell between a 3 HHT and a 4 HHT but I know my blade was sharp enough this morning because my face is still smooth this evening. I'd rather (personal opinion) have my shaving as more of an art than a science. It's just shaving.
The article that was linked above is very good, right up until it goes into the HHT1-HHT5 then it loses me (As Oscar just pointed out so well) But the easiest way to start is with a new DE blade and see what you have, myself I figured it out way way back by making a dumb mistake I read about the HHT 20+ years after I had been shaving witrh SR's and how so many people were having issues with passing it.. So I head up to the shave den and hone up a razor, pull a hair outta the brush on the counter and Bam, Bam Bam it pops so dang easy all down the blade.. I think now I am gods gift to honing.. So about 3 days later I am honing again I pull out a hair from the same brush and "Nutin Honey" nothing I do will get it to pop, I hone, I finish, I hone, I finish, finally I strop and Bam Bam Bam it pops again.. Then it finally gets through to my lagging brain, two different hairs,, that lovely bride of mine is using my brush My Hair - the first one, I learn will pop at 1k and from there on Her Hair - the second one, will not pop at all unless everything is damn well perfect after stropping.. I now have what we in the Gun Game call a Go/NoGo guage with the wife's hair, if I can HHT with hers I know that I have done it all right on the hones and strops -BUT- keep in mind that I could do that exact test and still have a chip or ding in the edge, so all the tests have value, the shave test having the most.. Any one of these tests can let a "Fail" through, that is why it is best to learn and use as many as possible, effectivly as possible when honing.. But I would start with the easiest hair you have accessible and a new DE blade and see what ya got going on..
Just to chime in here: Hair varies from person to person. Some are thin and some are thick. Some will pop on a razor and some may not. I honestly think the best way to use the hht in determining sharpness is to use the same type of hair consistantly when honing. Whether its from your wifes hair brush or from your own head. Get to know how it "pops" hair in relation to the shave and you will have half the honing battle won. Also those Sheffield wedges are very difficult to set right, especially when someone in the past thought they knew what they were doing. (Honed two this week like that).
As had already been said, the most important test is the shave test. I've had a few razors that will pop a hair but don't shave worth a darn an vice versa.
I Agree with JoeB, hair thickness and type aeries from person to person, when I'm honing and I've got to the 3000 grit stone I keep going until I can do the HHT on one of my beard hairs then onto the 8000 grit and I dont come off that until I can do the HHT on one of the wife's hair's (quite thick) then once I've gone through my strops I'm not happy until I can do the HHT on one of my hairs (very fine) and I'll keep going until I can do HHT about 1/8" of an inch away from my finger tips. If it can do that I'm happy and I know it's going to give a good shave.
Not important at all to me. I can do it, but have not reached a point to calibrate. I cut paper. ONE test, beginning to end. Buy a 10pack of 5x8 note pads. A years worth of identical test material. Test end to end with every test, no spot here and spot there. Test any time, not just when you have reached a specific spot. Like stropping, feel, listen, watch for tiny jerks of the paper or spots the razor quietly slides over without cutting. Can pick up a tiny chip long after your eyes and thumbnail cannot find it. Will tell of a feather edge (bur) instantly. Also recommended, convenient bench of some type, movable strong over the bench light, and magnifying goggles. When the razr weems to float through the paper making barely a sound, it is time for the strop and face test.
Paper ???? on a straight razor??? Nope not getting me on that one Edit: You mean for a bevel set right ??? but even that seems way too easy, at a 1k bevel set I could slice and dice confetti outta paper, but like the TNT you would have to re-set as it is destructive to the edge.. I remember years back some of the guys talking about a Wet TP test but that was a Knife Guy test,, again pretty useless above the 1k level
Hmmm, with all due respect, I thought I said " ONE test, beginning to end". If I had only known that razor edges were that fragile, I wouldn't have ruined the last 1500. I would not argue that the commonly accepted methods do not work, but would argue about the damage done by the popping arm hairs test on dry skin. Anybody else in the world testing by cutting paper, or is it really rocket science after all, that only works one way?
