Quote Originally Posted by Catrentshaving View Post
And that's pretty much what Glen means by calibration. Not all hairs will pass on different blades. On some of my razors I can do it ( I have fine hair ) and others won't. All shave equally well, it comes down to the shave test.
+1 my hair is so thick it will pass the HHT on a blade that shaves like a chopping knife. Maybe not quite that dull. But well before I would consider it shave ready. I only use the HHT to judge when I am getting close to a shave test. The quieter the sound of the cut the closer to a shave test I am.