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Thread: Thumb pad test

  1. #1
    Admin & Forum fixer Bruno's Avatar
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    Default Thumb pad test

    Last night I was honing a vintage Puma wedge, and I didn't feel like getting up and finding one of my wife's hairs, so I decided to try the thumb pad test for the first time ever.

    This was after the 4000 stage of honing.

    I wet my thumb and very lightly pressed my thumbpad on the edge. And when I say pressed lightly I mean just enough to actualyl feel that I touch something.

    Creepy.
    I cannot really describe the feeling because it is unlike anything I ever felt.
    When I touched the edge I felt it going through the ridges that make up the fingerprint. The place where my TP touched the edge felt very hot, like I was touching a hot plate, except there was also a feeling of electricity to it.

    I suspect this has something to do with the nerve endings getting stimulated by the metal.

    Anyway this is a useful test. Combined with the flow of water over the edge, it tells me everything I need to know.
    But it is also a bit scary.
    Happiness is a field, littered with the mangled corpses of your enemies. - Vlad III of Wallachia

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    Member AFDavis11's Avatar
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    Yea, it breaks the first layer of skin. Neat huh? I've never passed without extensive stropping off 8K though. Never tried 4K. I've found you can only do it 20 or so times before your not enjoying it . . . a little pain.

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    Senior Member Windcalmer's Avatar
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    I can't even do the fingernail test. Makes my skin crawl. LOL I can't imagine doing the pad test. You all get my respect for being able to!

    Funny because I can tattoo myself, but the fingernail test creeps me out. LOL

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    Senior Member Garry's Avatar
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    I like your description Bruno thanks

    I'm still unsure as to whether I'm actually doing the TPT correctly but I tend to feel like the ridges of the thumbprint catch the edge of the razor sort of like little hooks to me, it feels like the edge is sharp enough to slice right in but doesn't quite go there .
    This is a test I'd like to see done corerectly via a vid or something ..

    Again thanks for sharing your findings

    Garry

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    Member again CloseShave's Avatar
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    The more I hone razors the more I feel that the TPT is the most tell tale test. The feeling of a very sharp blade is unique and unforgettable much as you describe it. Any faults in sharpness are picked up as I run my thumb along the length of the blade.

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    Quote Originally Posted by CloseShave View Post
    The more I hone razors the more I feel that the TPT is the most tell tale test. The feeling of a very sharp blade is unique and unforgettable much as you describe it. Any faults in sharpness are picked up as I run my thumb along the length of the blade.
    +1

    that unique feeling of the edge, it's absolutely fantastic and really really hard to describe, but once I discovered it, it's been quite easy to tell when I can try the HHT.

  7. #7
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    I think doing the TPT might be a very personal experience. I, for one, have very rough skin on my fingertips, due to frequent work in my woodshop. A while ago, a friend was helping me out with some woodworking project. We were handling a large quantity of rough cut stock. By the end of the day his hands were loaded with splinters, while I had practically none. I remember that years ago, my hands would have been in the same condition as his.
    When I try to perform the TPT, even on a razor that shaves very well, I hardly gives me any sensation. It feels like I can push the blade till the point it will penetrate my skin and draw some blood. It doesn't make any difference if I try to perform it on a sharp kitchen knife, a plane blade, or a razor (all three will easily shave arm hair, though)
    I try to work around my problem by using a lower part of my thumb, but the lesser amount of nerve endings makes it harder to feel the sensation the blade is giving me.
    On the same note, I don't feel intimidated by the TPT either, although the mere thought of dismembering one or more fingers with one of my woodworking machines scares the hell out of me.

    Maybe I should try to develop an alternative for the TPT...
    the DAL-test: Drag Across Lip test
    even better, the DAG-test: Drag Across Gingiva (gum) test

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    Senior Member ericm's Avatar
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    I'm probably doing it wrong, but I never got much from the TPT, even with razors that shaved very well. What does work for me is how the razor feels on the hone when it is getting sharp. The drag increases dramatically, and I know I'm there.

    E

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    Senior Member Milton Man's Avatar
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    I really like the TPT to see if the entire length of the blade is getting sharp, or if some areas are sharper than others. I'd have to day that the sensation, for myself at least, is one of stickiness...I'm looking for a feeling of the same level of stickiness as if I'm lifting my finger off used scotch tape...

    Of course, I think it's what you're used to in terms of feedback...that's just how it works for me.

    Mark

  10. #10
    Str8 Apprentice, aka newb kerryman71's Avatar
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    I appreciate your description. I've been
    searching to see just how this test
    is performed. This clears it up. Thanks.

    John

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