Thread: Sharpness Tests

I've been reading around the forum and the various bits of literature I can find and I've found a rather vast multitude of sharpness tests. I've seen the thumbnail test, the hanging hair test, the arm-hair shaving test, etc. I was wondering what you guys think is the most effective, most telling, or most appropriate to use in one situation or another.

The shaving test is the only one that is true.

Well, I guess the shave test is THE one, but I use the HHT now that I can actually hone an edge to that condition. It's quite a spectacle too; more bad-ass than actually shaving with a straight raozr IMO.

I use the thumb test while honing to make sure the edge is developing, and the hanging hair test to see if it's good enough for my face. I also sometimes resort to the thumbnail test, but only to check for irregularities.

Agreed, I think you'll save some face discomfort if you follow the hanging hair test. Now that Im touching the blade to the outside of the arm hairs I'm getting good feedback on that (I think). Another test I use is stropping. It feels different as you strop with a sharp blade. Probably not helpful to you at the moment.

Hmmm...I guess what I really need to develop is a frame of reference for those tests and the feel on the strop etc. I think I'll wait for my new razor to come, send my old razor to classicshaving's sharpening service and then test that razor out and see how it feels with the thumbnail and hanging hair so I know what "sharp" feels like. Thanks for the input guys.

All the tests are good but only real test is the shave. I have one razor that defies the HHT yet shave great.

I have to go with those that say shaving is the real acid test. I've had razors that have passed every test but still were not shave ready. With time and experience I can tell by shaving my arm hairs the way the razor cuts and feels if it is shave ready and 9 out of 10 times its accurate for me but then there's still the 1 time its not.

Different tests are used for different purposes and stages.
The thumbnail test is used to check for nicks and to see if the blade has developed a sharp bevel. The finest hone to use this on is the 4000 hone. using the thumbnail test on a 6000/8000/12000 edge would harm the edge.

After the 4000 hone use the thumb test. It tells you when the edge has some bite. You move the pad of your thumb "across" the blade, not along the length of the blade.

The Hanging Hair test is the next finer indicator. My standard is that the razor must pass the HHT on the 8000 hone before I move on to anything finer.
In this test the razor is held stationary, only the hair is moved.
The hair is held, root end out, with the curve of the hair bending down extending 1/2-3/4 inch from the thumb. Bring the hir down over the edge of the blade. As your razor becomes sharper you will "feel" less of the cutting action. It will go from a "tug" or "chunk" sensation to one of no sensation.
Then its time to move on to the finer hones.


Hope this helps,