Different Thumb Nail test

When the subject of new Bokers came up I started searching around and a Boker ad talked about their TNT.

They are not checking the bevel with this test, they are looking for the flex of the edge, to see if it would bend easily and snap back. In other words they are checking the quality of the grind.

They were sneering at blades that couldn't pass this test calling them "axes". I remember seeing a woman wearing a ring on her thumb in a video in, I believe, the Dovo factory doing this test. I didn't understand what she was doing at the time.

Comments?

Can you post a link to this TNT? I use the TNT to check knives for sharpness, but IMHO razors need more. I use the test where you run your thumb along the blade to see if it sticks. Yeah, it's a scary test, but it works once you get the hang of it. The hanging hair test is another good one, but the shave is the only definitive test.

It is a "Grind Test" they are testing the thinness of the grind by the flex of the blade, some also believe that it can test the temper of the blade by an experienced person.. The "snap back" tells that

For the normal person it can check for the bevel evenness, the grind evenness,,, and it is a definitive test for cracks...

Quote:

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Originally Posted by ziggy925

Can you post a link to this TNT?

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From: Boker offers Straight razor for all requirements.

"Through 170 individual production steps, the new and exclusive Boker straight razors are created. A guarantor for the highest quality is the successful "finger nail test". Only the edge of a perfectly ground blade can be visibly bent on your thumbnail and returns immediately to its original shape when released. Cheap blades are too thick to do this, and for that reason they are refered to as "axes" by the experts."

I do a very similar "screwdriver test" (where I flex the edge of the blade against the shaft of a screw driver) for most of my better knives when I first get them and regrind their secondary edge.
I haven't thought to do it for the straight razors since they are so thin. I am worried about warping the edge permanently and about how it will affect the honing process afterwards.
I suppose Boker is so confident in their steel and heat treatment that their blades are "guaranteed" to withstand a reasonable amount of elastic deformation. I still wouldn't do it though.