Problem with 3 finger test: Tips always feel duller

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KennyB

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Jan 19, 2010
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So I've noticed lately while employing Murray Carter's 3 finger test that the tips of my knives always feel dull for some reason. Only one this wasn't true for is my Kershaw Needs word with a wharncliffe blade, but all my other knives are pretty much drop points or clips and I'm wondering if I'm actually not getting these parts as sharp as the rest of the blade, or if it's just the 3 finger test making it seem that way.

Reason being is because if the tip area feels duller than the rest of the blade I will focus a little more there on the hone, but it never really winds up feeling equal. Meanwhile with all the other "tests" ( shaving, paper, etc ) it seems to cut just as well, and with magnification (30x) it looks the same.

My basic idea is that maybe because by the time I get three fingers to the bellies and tips of my knives, it puts my fingertips in a different distance in to each other and makes it feel a bit different than it had up on the flat section of the edge.

Does anyone follow what I'm saying? On my droid so I can't really go into more detail...
 
Change fingers orientation by touching with palm up and palm down, usually the index finger is less sensitive (probably toughen by sharpening knives - lol). For knives that not crazy sharp, play musical notes - essentially only 1 finger is touching the edge at a time. There is always a 200x+ usb microscrope way to see what's going on at the tip.
 
KennyB said:
So I've noticed lately while employing Murray Carter's 3 finger test that the tips of my knives always feel dull for some reason. Only one this wasn't true for is my Kershaw Needs word with a wharncliffe blade, but all my other knives are pretty much drop points or clips and I'm wondering if I'm actually not getting these parts as sharp as the rest of the blade, or if it's just the 3 finger test making it seem that way.

Reason being is because if the tip area feels duller than the rest of the blade I will focus a little more there on the hone, but it never really winds up feeling equal. Meanwhile with all the other "tests" ( shaving, paper, etc ) it seems to cut just as well, and with magnification (30x) it looks the same.

My basic idea is that maybe because by the time I get three fingers to the bellies and tips of my knives, it puts my fingertips in a different distance in to each other and makes it feel a bit different than it had up on the flat section of the edge.

Does anyone follow what I'm saying? On my droid so I can't really go into more detail...
Click to expand...

The point highlighted above is the only important thing. If it cuts well (to your expectations), and looks like a clean and complete apex under magnification, I wouldn't worry about the 'feel' of the edge under your fingertips. Some of the most wickedly-sharp knives I have, feel deceptively 'smooth' by my fingertips, and I think using the 'feel' aspect is way too subjective and prone to mis-interpretation. Too many variables play into it, with the individual character of one's own skin probably being the biggest.

The only thing I'll add, which might impact the 'feel' by your hand, is that most upswept blade tips will have more obtuse edge angles, even when sharpened to a perfectly clean apex. It's the result of the edge sweeping upwards into the thicker steel of the blade grind, assuming the bevel width (measured from edge to shoulder) is constant.
 
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Try switching hands. If it really is cutting just as well as the rest of the blade don't worry about it. My bellies and tip areas almost always feel a little sharper using the three finger test, and I believe they actually are tho only by a very small degree. The more I use this test the more reliable it gets...

If it fells less sharp to both hands/fingers then it probably is.
 
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