Thread: Clarification re Thumb Pad Test

Even after looking at the wiki I'm not sure what direction I move the thumb when doing the TPT, or what amount of pressure to apply.

1. If the toe of the razor is north, and the heel is south: am I moving my thumb north-south or east-west?

2. With the understanding that I am not mashing down, or anything close to it: is it just a light brush across or do I add a bit of pressure? If the latter, does the pressure increase during the movement or remain the same.

I see HHT vids, but since the TPT is supposed to be more useful, it'd be helpful to see a TPT vid or two.

Here is a honing vid where you can see Lynn test the edge with his thumb from time to time.

When I was getting into it Randydance advised me to take a DE or SE blade, a new sharp one, and practice with that so I would know what sharp is supposed to feel like.

I hold the spine in one hand with the heel down and the point up. I touch my thumb to the edge lightly and kind of scuff it to feel it is 'sticky'. If it isn't sharp you pad will king of slide right along. I work from the heel up to the point.

Not enough pressure to cut yourself but enough to either grab or slide.

Originally Posted by JimmyHAD

I hold the spine in one hand with the heel down and the point up. I touch my thumb to the edge lightly and kind of scuff it to feel it is 'sticky'. If it isn't sharp you pad will king of slide right along. I work from the heel up to the point.

Not enough pressure to cut yourself but enough to either grab or slide.

So when you scuff it, are you moving it north-south -- i.e., in the direction of the heel or toe -- or east-west? Or just pressing down a bit?

To answer directly, if the toe is north, and the heal is south, you would hold the razor edge-up in your right hand, and move your left thumb across the edge from east to west.

If you tried to move north/south you would slice your thumb open.

I should add, that this should be done with no pressure at all. The razor edge is easily damaged, and so is your thumb. You just want to barely skim the edge with your thumb.

You can repeat the process at various points along the blade to check that the edge is uniform

This is a hard technique to describe, it is even hard to do on video...
The best way to learn it is exactly what Jimmy and Randy said test a SE or DE razor to get the feel down...


I hold the razor in one hand blade up an down and kinda bounce the pad of my thumb off of the edge as I walk it down the edge from toe to heel...

You will feel the edge stick as it cuts into the top layer of skin....This is the object of this test no matter how you accomplish it....Some people just press the pad of their thumb onto the blade edge and test by how it feels as it digs in...

OK for real here, if you are not smart enough to do this without cutting yer thumb, you might really want to reconsider putting 3 inches of the sharpest steel known to man against your throat and Carotid arteries....

I started by going west-east ( left to right) then I got bolder and started going south-north (heel to toe) very gently. The movement of the thumb resembles a "u", a very short gentle movement. The key point is to be consistent in performing the test. Eventually you will notice the changes more and more.


Hope this helps,

I go north-south with my thumb (and still manage not to slice it open). My technique is most likely like how Glen & Randy are describing. I wouldn't necessarily call it "bouncing," but I lift my thumb as I move to each area to test.

You test a razor by going North to South.
You are specifically testing the ability of the edge to CUT into the outermost layer of skin. For that reason you have to go N to S, not East to West as is done when testing a knife. Because you are touching it lightly, there is no risk of cutting so deeply as to draw blood. The drawing sensation as the blade LIGHTLY cuts into your dermis is what you are looking for a gauge. You can help train your ability to judge a sharp razor by practicing on a DE razor blade.

I go north south. Absolutely no pressure applied! I've got a nice thick layer of skin on my fingertips, so it's pretty safe. I've heard xman describe that he goes east west, but that's not for me. I feel i'm less likely to damage the delicate edge doing it the way i do.
Each to his own method.
I was advised to get the feel for it on a DE blade too. I've got Feathers. They're sharp. Really sharp, but not nearly as sticky as a my straights seem.

Absolutely, North/South. I think it would be fair to say that the thumb doesn't really even need to move. If its not sticky at first touch then it ain't going to get any stickier. The razor only feels sticky after proper stropping, for me anyway. Beforehand the razor usually just wants to slide.

Oh, and yea, don't cut your thumb open. That is bad form.