Thumb test

When I use my Naniwa stone progression or even my JNats I can run my thumb pad over the blade and it really sticks. When I look at the edge under a 40 magnifier the edge looks even and smooth. When I shave with it I find it a little harsh. If I go back and do 5-10 laps on my Escher under running water and try the thumb test my finger doesn't stick and in fact if doesn't feel sharp at all. Under the glass is is very polished. The shave is smooth, no tug or irritation. I also try the arm hair test and it cuts hair easily with or without the Escher. Just curious to see if others have had the same results.

I take my blades to a Zulu grey after 12k Nani. for the same reason your talking about. I imagine what is happening is at 12k level the edge has little sharp grains pointing in all directions. Grabs the skin better than something smooth. An analogy would be , a fresh cut piece of plywood. Knock off those splinters and the edge is still sharp but not as splintered. That's the picture in my mind anyway.

Some of these tests can get a little confusing. For instance, the controversial HHT can be easier to accomplish on a low-grit, "toothy" edge sometimes than a fully honed one. In any case, there are so many variables involved that one must always calibrate it to specific types of hair, the way you hold and orient it, your hones in your hands, etc.

The thumb pad test should be used with caution after a full bevel set, especially on a full hollow edge. Ask me how I know.:D

Everybody has "tests" they like to use. One I just discovered (thanks to Dr. Matt on YouTube) is the cherry tomato test. It will tell you if you have a good bevel all the way across in a very visual, tactile, reliable way. Furthermore, the more you refine the edge up the grits, the more effortlessly it slices through the skin,; in that sense it is very progressive and easy to interpret. I love it and plan to keep using it (and it gives me something nutritious to snack on while honing lol).

Edit: I haven't gone down the Escher rabbit hole yet, so can't speak to that. In fact, I'm just now learning how to use a Trans Ark and JNat. But I have heard the same thing about Eschers before.

I use the thumb pad test often, but it's one of those things you've got to really know what a shaving edge feels like. It does grab a little differently than a set bevel, a 4k level blade, or one that's shave ready. That said...I have gotten false positives. With just about every test known to man really. The Torrey straight that I was just messing with is a prime example. It felt to my thumb pad like it was sahving sharp. It treetopped arm hair all along the blade. But the shave was kinda bad. Closer inspection with the loupe revealed some burrs I didn't feel near the toe that didn't affect ability to treetop arm hair but did make it tug and pull beard hair.

I've come to the conclusion that, no matter what test you use, all you'll really know is that you're headed in the right direction until the shave test.

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Originally Posted by Marshal

I've come to the conclusion that, no matter what test you use, all you'll really know is that you're headed in the right direction until the shave test.

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hehehe I think maybe I have heard that a time or two :p


Personally the farther away I get from the 1k the less touching of the edge I do..

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Originally Posted by gssixgun

hehehe I think maybe I have heard that a time or two :p


Personally the farther away I get from the 1k the less touching of the edge I do..

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And the same applies to me with my use of my stereomicroscope...

I'm with those guys^. I test for sharpness at the bevel setting stage. After that it's pretty much visual until I come off of the finisher. I do use the HHT after that but the shave test is all that really matters.

So as said, tests point you in the right direction, the TPT can take a while to calibrate, (understand what you are feeling) what TPT and hair test do not tell you is, if the edge is chipped and if the Whole edge is meeting.

Look at it, If the shave (the decider test) is harsh, something is wrong. Look at the edge make sure the bevels are fully meeting and the edge is not microchipping.

Typicaly, I use the TPT to see if the edge is coming together, hair test at the higher hones, as a quick test of keenness and visual test all through the range, to test for fully meeting bevels and chipping.

How much magnification are you using? Look straight down on the edge.

Congratulations, you have enhanced the calibration of your thumbpad test. As with any other test, you need to take an edge with a performance you have verified by shaving, then run your test and remember the results. And, in the future, run the test in the same way under the same conditions.

Personally, I rarely do anything to test the edge after the bevel is set (other than shaving, of course). If I do check something, I usually only use my naked eye to check light reflecting off the bevel to see what the scratch pattern is like.

Quote:

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Originally Posted by gssixgun

hehehe I think maybe I have heard that a time or two :p


Personally the farther away I get from the 1k the less touching of the edge I do..

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Probably because you're the one I learned that from. But now I've got a little trial and error experience to corroborate it with. :beer1:

Also agreed on pawing the edge less further from the 1K. At most I give the blade one light touch at the heel, middle, and toe to be sure it's uniform and feels 'right.' Strop, shave test, sally forth.

I only TPT after a 1K stone. Not because I'm concerned about harming the edge but because I only get that "sticky" sensation at 1K. After that the edge feels smooth and I can't distinguish any further refinement with the TPT. YMMV.