Thread: The thumb method to tracking an edge

Honing a razor is easy you run the blade across the stone in the X pattern with only enough presser to keep the blade flat on the stone. Keeping track of what you are doing is the hard part. I chose the old timers thump test. But you have to teach yourself how to feel the teeth and fin on the cutting edge of the razor. I studied the feel of a razor against a wet thump for weeks to learn the stages an edge goes throw. Here grasshopper is what I have learned.

1 Your thump has to be wet for about half a minuet before you can feel the fin on a razor. You just barely touch the razor, remember you are feeling a microscopic fin and you can brake if very easily. Here less is more.
2 The best and fastest way to learn to feel the fin is to keep track of the blade as you hone it. But if you keep your thump wet as long as it takes to hone your razor it will get to soft so you have to keep it dry between tests. Buy the way I almost never hone a razor in one setting. Give your skin a chance to rest before you put the final touches on it. The nerves in your skin will get tired after about 20 minuets, it has to do with the chemicals the chemicals they use to transmit signals and how fast they can make more. I just set the blade aside and finish it later.
3 Test your razor than run it across the stone a few times. The stone you use is your choice I start on the 8k and if I don’t feel the fin starting to form after about 4 passes I do the 4k a few times. Your thumb will tell you what to do. You will know the fin when you feel it and you will feel the teeth as well.
4 When I first feel the fin on the 8k I give it a few more strokes to feel to grow. Remember your learning to feel the fin, you already know how to hone a razor. Now I go from the 8k to the 15k and back again. Usually 1:1 or 1:2. The 8k builds up the fin and the 15k makes the teeth finer. You have to have the finest teeth you can still feel and still have the fin! If either one goes away the blade will not cut well. You can do the same thing with a 4k/8k stone. Your thumb will tell you when to use the courser stone more to build the fin and when to stick to the finer stone. At the end I go one or two strokes on the stone at a time and strop a little to help refine the edge. I use a medium fine and supper fine strop the same way I use the stones. When do I go the strop? When the edge is getting to the point where I can just feel the teeth, I strop 10 or 20 times to see if it makes the teeth finer. If not I stone the blade some more. No canvas! (the fin should feel nice and large when you are done) As you can see the better you can feel the blade with your thump the sharper your blades will be.
5 All the old men (90 + years) I have talk to tell me the same thing about pasted stops. They are very good for polishing the cutting edge of the fin, but they will wear is down and it needs a stone to build it back up.

Well that is what I have learned so far. Most of my progress has come in the last three week so it takes very little time to learn this. Happy shaving.

Buy the way do you think this is worth posting?


Mason

Thank you for posting this Mason. As I have told you, I think your honing job on the TI 7/8 was absolutely superb. Popping hairs and singing right out of the box. I am wondering if you can describe the thumb test in detail.

I remember when I watched Murray Carter sharpening video in horror as he explained how you drag three finges across the edge in a certain manner to test it's toothiness. Once I got over my inital trepidation, it became a very useful test, but I am a little nervous about the razor thing.

This is an interesting thumb test and I understand it's working great for you, but it's not the traditional one. I used to go to an old time barber who did it exactly the way it's shown in the baber's manual. Actually, it's a thumb test and a thumbnail test. And it's much simpler and quicker than what you do.

Barbers were not in the business of honing razors. It was something that was done on a barber's hone momentarily. Once in a while I would see the barber take a couple of swipes over to the side and go right to the strop. Once in a while he would do the thub test on a razor during or just before a shave. He didn't soak his thumb. And often I'd see him go to the strop and test again and strop again. All this happened in a matter of seconds.

Sometimes when there wasn't a customer, he would take out a razor and spend a little more time on the stone (a minute). He would test it on his thumbnail and then go to the strop. So, he worked with a baber's hone and a dual strop, but only the leather when honing. If a razor required any more work he would send it out for service. Out of curiousity, I talked to him about it a few times. He said he usually only had to send out a razor if it was damaged.

Those tests were just as shown in the manual. They were quick and easy and not a big production. I was not able to make a razor keen until I learned how to use those tests. No razor, no matter who did it, passes the hanging hair test for me. I think my hair is too fine. So, I combined these tests into an organized procedure. They're done with a damp thumb or thumbnail. It'll even work dry, but it's less sensitive. The procedure is like this:


THUMB

Do this test when you first pick up a razor.


Support the razor gently with the edge pointing up and lightly drag your thumb across the edge in a few places along the blade:

1) If the thumb slides easily and there’s no grab, go to the thumbnail test;

2) If the razor grabs slightly, do 3 swipes on 8K stone and 15-20 on strop, then repeat test;

3) If the razor grabs but you feel no edge do 10 swipes on strop, then repeat test;

4) If the razor grabs really well or moves with the thumb, you will also feel an edge- shave.





THUMBNAIL

You have failed the thumb test.


Rest the blade on top of the thumbnail with edge pointing down and tilt the thumb downward slowly. If the razor slips sideways go to the 4K stone.

If not, bring thumb back to level and slide the blade on thumbnail from one end to the other:

1) If the blade slides smoothly and doesn’t dig in, go to the 4K stone (dull);

2) If the blade digs in but doesn’t move smoothly, go to the 8K stone (coarse);

3) If the blade moves smoothly and feels like it’s digging in, but you feel a gap or bump, you have a nick at that spot;

4) If the blade moves smoothly and feels like it’s digging in, go to the strop;

5) If the blade digs in but makes a rough, scraping sound you have an overhoned edge.


I described this in the simple form with just a Norton 4/8 (or a two sided barber hone) and a strop. I'm a perfectionist so I go to a fine barber's hone (from the Norton) and or pasted strops before the leather. Actually, I prefer pasted strops if I have time. The .5 and .25 are like 50K and 100K grits, so they're slow and you're not going to mess anything up if you test as you go along.

A feature of this approach is that you're always moving up to a finer medium. There's no turning back. And you're doing it when the tests show you've maximized that step. Usually, each finer step begins to show some improvement in the edge. When it stops you move up to the next finer level.

If you're only using the thumb, how do you detect an invisible nick or a wire edge, which can feel like a good one?

a wire edge is best seen using light reflection in my opinion. It is pretty easy to spot if you are looking for it. That goes for nicks in the blade as well.
Of course if your talking about micro nicks then I like to use my jewelers loop to look things over when from time to time.

Looks like we've made some progress , in the past 5 years .

In what direction?

Another blast from the past, or as mparker described it, a zombie thread. What helped me get the TPT was Randydance suggesting to me to take a new DE blade for getting the feel of a sharp blade. He also suggested I use the TPT in conjunction with the TNT while setting the bevel. This lets the honer feel the progress as the edge is approaching a level of sharpness.

Of course once the TNT is passed it is not repeated and the TPT is relied on. I work on bicycles quite a bit and my thumb pads are callused which makes it more difficult to use the test. I tend to feel the edge off to the side a bit where the callus is less developed.

Originally Posted by AFDavis11

In what direction?

I'm not sure of the direction , but we are making progress .

Well, at least now a days we don't use the word "thump" as much.