Thread: Need diagnostic help...

Joe put it in more eloquent words than I did. Listen to him Josh, as he knows what he's doing and then some.

Joe, as I understand it, the thumbnail test consists of wetting your nail and drawing the razor's edge over the surface of the nail with as little pressure as possible. I've been trying that, and the edge does seem to bite in just a little, leaving a small groove, and it feels consistent over the whole edge. It doesn't slip or feel rough. Does it sound like I'm on the right track?

Originally Posted by joshearl

... I lapped them on 600-grit sandpaper and glass ...

This could be part of your problem. I lapped my Norton combination water stone recently with Silicon Carbide which was fairly coarse and the result was the surface was just too coarse to get a good edge on the razor. 1mm would be fine and the next couldn't cut crap. I'd go to 1000-2000 grit high quality wet/dry for finishing that job to make sure everything is working optimally before you try another pyramid.

And I'm going to disagree with, Joe ( AGAIN!!) but only just a little. While a whole pyramid (up to 25 4k laps) is overkill when you're very close, I often find that if I'm continually stymied trying to finish an edge off, I can go back and with a pyramid up to 10, get a good foundation for the completion of the edge. each circumstance is unique and you'll have to decide what you think you should try.

X

Originally Posted by joshearl

Joe, as I understand it, the thumbnail test consists of wetting your nail and drawing the razor's edge over the surface of the nail with as little pressure as possible. I've been trying that, and the edge does seem to bite in just a little, leaving a small groove, and it feels consistent over the whole edge. It doesn't slip or feel rough. Does it sound like I'm on the right track?

That's right. Just add one initial step. Allow the edge to rest on the fingernail and begin tilting the thumb down. You should be able to tilt down to 45 degrees without the blade slipping sideways. If it doesn't pass this test it's dull.

The thumbnail test is done in a few places along the blade. I like either end and the middle. You may get different results at different spots. All spots need to pass the test. For a more detailed explanation of what the test results mean, go to classicshaving.com, the "how to ... and why" section. See the subsection on honing.

From your descriiption, it seems your blade may pass the test. Just make sure it passes the tilt test.

Originally Posted by xman

And I'm going to disagree with, Joe ( AGAIN!!) but only just a little. While a whole pyramid (up to 25 4k laps) is overkill when you're very close, I often find that if I'm continually stymied trying to finish an edge off, I can go back and with a pyramid up to 10, get a good foundation for the completion of the edge. each circumstance is unique and you'll have to decide what you think you should try.

I don't disagree with this. I did say that the partial pyramid should be done when your close. It doesn't make sense otherwise.

Originally Posted by Joe Lerch

I don't disagree with this. I did say that the partial pyramid should be done when your close. It doesn't make sense otherwise.

Then I agree not to disagree.

X

Well, the pyramids seem to be working. I did five or six last night, and this morning the razor was actually shaving, although it was tugging badly around my chin. Although it wasn't even in the neighborhood of a close shave, it did knock my stubble down quite a bit with one pass.

The edge does seem to pass the 45-degree tilt part of the thumbnail test. It's starting to bite more as I drag it across my nail, too.

I'm realizing that what I thought was a smooth-looking edge (viewing through the 60x Radio Shack microscope) was actually more like a crosscut saw blade. Now my edge is more polished, and the teeth are so small I can barely make them out.

I'll do a few more pyramids tonight, I guess. The heel and point of the edge still seem like they need work.

Is it possible to develop a wire edge if you stick with the pyramids and use light pressure?

Originally Posted by joshearl

The edge does seem to pass the 45-degree tilt part of the thumbnail test. It's starting to bite more as I drag it across my nail, too.

As soon as you get a bite and it feels smooth, stop using the thumbnail test. It will dull the edge. That's when you move on to only your sharpness test (HHT).

I'm realizing that what I thought was a smooth-looking edge (viewing through the 60x Radio Shack microscope) was actually more like a crosscut saw blade. Now my edge is more polished, and the teeth are so small I can barely make them out.

At 60x it should look almost perfectly smooth. If you can see chips or a rollercoaster pattern that's more than 10% (usually those will produce a slight bump as you slide the edge over the nail) of the bevel, you need to work some more on the 4K. This is all part of setting up the edge. Once the edge is set you can move on to the pyramids, and no more thumbnail test.

As you noticed, there will be some sharpness after the edge is set. That's why you need to do a sharpness (HHT) just before the first pyramid. You probably won't be there yet, but you want to know how close you are. If you just happen to be close you don't want to overshoot the point of keeness by doing too much. If you happen to be lucky you may be real close, and you could end up requiring less than a full pyramid.

Is it possible to develop a wire edge if you stick with the pyramids and use light pressure?

Yes. That's why I suggested a sharpness test before the first pyramid. If you happen to be close, a full pyramid may put you over the top. If you create a wire edge, it could set you back a lot after the wire comes off. Overshhooting is the reason why so many newbies end up doing endless pyramids and never quite getting there.

If it feels like you're almost there and suddenly the sharpness drops way down, if you had good clean metal on the bevels, you've probably gone over the top and just removed a wire edge. Grab the microscope and see if you now have a new rollercoaster pattern. If the metal looks clean and not discolored or microscopically rusted (in spots) you probably removed a wire edge.

Joe,

Very intuitive point, as some, I think, believe the pyramid by itself wards off overhoning and wire edges. Very good thread.

Originally Posted by FiReSTaRT

. . . 3" is ok if you can't find the 2".

2" saves a dollar or two in the short term but 3" is much much much much much better .