What does it mean when you slide the razor across your thumbnail and the razor vibrates as it travels across instead of sliding along smoothly? Like when you slide a couch across the floor or something. I'm pretty sure that means something is wrong, right?
Thumb nail test question
- Thread starter Friedramen
- Start date
Rhody
I'm a Lumberjack.
Never heard of that why do you do it
A sharp razor would bite the nail if you hold it in angle higher or same as honing angle.
If you drag the razor edge in an very low angle( close to 0) the behavior depends probably as much on the nail as on the razor edge.
If you drag the razor edge in an very low angle( close to 0) the behavior depends probably as much on the nail as on the razor edge.
Hair and fingernails are made of much of the same material, keratin. When you pull a dull razor overy your beard it does not cut, grab, shear, cleave, catch. Over your nail with a little practice you can recognize these same sensations. With a shavable razor drawn upon my fingernail, the sensation I get is "if I don't stop, it will cut right thru and draw blood". How easily do you get scared and back-of? Try it yourself, test your squeamish factor. Then you can judge for yourself. Shaving is the ultimate proof, but thumb nail test or the awkward pinky finger test, HHT test or tree trimming all will give you feedback as indicators for your mental library of what sharp really is, or how sharp is sharp enough.
Alex
Alex
I hold the razor perpendicular to the nail, or vertical, and drag with the weight of the razor alone. There are many nerve ending under the finger nail.
If there are any irregularities (small chips, etc.) you will feel them. I actually use the end of the nail.
If you're feeling adventurous, try using a moistened ball of the finger after stropping.
You only need to drag it a short way and you will feel it dig in (smoothly) move the blade to another location and repeat to check the entire edge. Its the old school way!
Very small chips or micro chips can be hard to feel but you will develop the skill to feel them.
If there are any irregularities (small chips, etc.) you will feel them. I actually use the end of the nail.
If you're feeling adventurous, try using a moistened ball of the finger after stropping.
You only need to drag it a short way and you will feel it dig in (smoothly) move the blade to another location and repeat to check the entire edge. Its the old school way!
Very small chips or micro chips can be hard to feel but you will develop the skill to feel them.
Wobble would make me think a very chewed up edge. Like something just off a buffer wheel or a 20-160grit hone.
That's the correct way to do the test, put the blade on the nail to see if it bites or skips, then drag it through. If you feel chatter, then the bevel/edge is not done correctly. Reasons for the chatter can be a rough apex, an undulating edge width, or both of the above. Really wacko striations can do it too - like from doing circles on a SSOFGR stone.
This is the test in the old barber manuals. I do this with every razor I hone, and have the marks on my thumbnail to prove it.
The manual talks about dragging the razor over the moistened thumbnail at the half-moon point - that white half-moon coloration right next to your cuticle. That's how I do it. It's supposed to give the best feedback due to nerve endings etc. But you can do it anywhere on the nail your comfortable, you just have to do it there continuously so you can distinguish the feedback.
The sensation you're describing indicates a rough edge. The blade should dig into the nail smoothly and consistently with no jittering or vibration along the whole length of the blade. This indicates a well honed edge.
Years ago this part of the barber manual (from the 1930's through the 1960's, I believe) was posted as pictures someone scanned. It described the various sensations and their meaning. I have no idea if it's still posted anywhere anymore so I can't post a link.
I have one of the actual manuals from that era in my library, I'd have to dig it out and see what it says.
One of the greatest problems with this approach is that it was intended for learned barbers to teach new ones the various sensations first hand. We don't have that available to us so trial and error is the only guide.
Chris
The manual talks about dragging the razor over the moistened thumbnail at the half-moon point - that white half-moon coloration right next to your cuticle. That's how I do it. It's supposed to give the best feedback due to nerve endings etc. But you can do it anywhere on the nail your comfortable, you just have to do it there continuously so you can distinguish the feedback.
The sensation you're describing indicates a rough edge. The blade should dig into the nail smoothly and consistently with no jittering or vibration along the whole length of the blade. This indicates a well honed edge.
Years ago this part of the barber manual (from the 1930's through the 1960's, I believe) was posted as pictures someone scanned. It described the various sensations and their meaning. I have no idea if it's still posted anywhere anymore so I can't post a link.
I have one of the actual manuals from that era in my library, I'd have to dig it out and see what it says.
One of the greatest problems with this approach is that it was intended for learned barbers to teach new ones the various sensations first hand. We don't have that available to us so trial and error is the only guide.
Chris
Right. I've taught this to many people in person and they get it in no time. I get a bevel nearly set and then show them the TNT, then have them do it and tell me where the problem areas of the edge are. If their assessment matches mine, I know that they are feeling the same things as me.
One caution; It sounded to me like the OP was using this test on a finished razor, using TNT as a test for shave readyness. I reserve this test for bevel setting and never do it past the 1k -3k level. I always follow it with a few strokes on the bevel setting stone to repair the damage that is done by the test.
- Thread starter
- #10
I'm doing it off a 1k only
Skin only for stropped razor!
I've always done the TNT with the blade perpendicular to the nail, as a method for determining if the bevel has been set. It should grab there. At a more advanced stage, I find that the edge no longer grabs, so the TNT is no longer useful there to me. Glad to know that stone and strop does the test head-on, like me, and I am grateful for El Alamein's comment about doing the test at the half-moon point; hadn't heard of that before. For someone new to the TNT, I would suggest trying it off a fine DMT for starters. No way to miss it there.
Last edited:
This is also mentioned in the old barber's manuals. The blade should grab the moistened skin when you go to pull it across (don't keep pulling or you'll cut yourself). If it does that then it's supposedly ready.
I can't recall if the barber manual says to do it before initial stropping or not. I want to say that it recommends the thumb skin test after stropping and to avoid the thumbnail test at that point but I'll dig it out and confirm. But S&S's advice is sound advice either way. I don't really do this test, myself, so I can't recall at the moment. I rely on the HHT after stropping as I've perfected it for my use.
I will say that I do the thumbnail test right up to after my last grit hone (I only go to 8k as I find no benefit, personally, after that). And I've had no issues with it.
Chris
Generally speaking, It's possible and safe to use the TNT up until about 3k or so. I hardly ever use it for razors but when I do it's always at the 1k-ish stage. But I have used it further along.
I start the blade on an angle to the nail, if the blade slips off and won't bite in, the apex isn't 'there' yet. Edges failing that approach may pass the perpendicular test. For the sake of consistency, I use the same general angle and place each time. I always test north of the lunula.
I start the blade on an angle to the nail, if the blade slips off and won't bite in, the apex isn't 'there' yet. Edges failing that approach may pass the perpendicular test. For the sake of consistency, I use the same general angle and place each time. I always test north of the lunula.
Last edited:
As I have always used the perpendicular, I'm curious as to what angle of approach you are using.
This is more to check the bevel set. Funny, they don't mention in the manuals how to check for that. They describe the method and sensation for quality of edge formation only.
Perhaps they are one and the same. A properly set bevel will dig in nicely when tested vertically.
Fingernails curve across mutliple axes, so the concept of what is 'perpendicular' or any other exacting angle, becomes a murky concept here. So, I opt to keep it simple for what is a simple task - I don't check with a protractor. The approach is angled, somewhere near the mid point.
Okay thanks. I'll take that as around 45 degrees. I suppose that would help to show from one bevel to the other, so I'll give it a try next time.
skip to 5:17
Similar threads
