Thread: How sharp can you get without a set bevel?

have you tried the black marker test, take a black magic marker and blacken the edge on both sides , do a few strokes on the film then look at the edge with the loop and it will tell you if you have a set bevel, if you see any black left on the edge that means that the bevel is not right .

Originally Posted by ronnie brown

have you tried the black marker test, take a black magic marker and blacken the edge on both sides , do a few strokes on the film then look at the edge with the loop and it will tell you if you have a set bevel, if you see any black left on the edge that means that the bevel is not right .

I just tried that out on the 5 micron film, only ever done it before on the coarse film. Within 5 strokes the spine and bevel on both sides seems perfectly clean except for a little bit of the heel on one side. Actually it's a lot more even than I thought it'd be, especially at the toe, which means I probably raised the heel a tiny bit in the same way that's worn it down.

Right now I suspect I'm making sloppy strokes as I go along, alternately lifting the heel very slightly sometimes and dragging the edge along the corner of the hone, ruining my progress.

I've used 2000 grit sandpaper / 5 micron film / CrOxide pasted strop successfully. [I'm in Canada, close to a Lee Valley store.]

I check for a "set bevel" with a 10x loupe. If the bevel is set, and you check with a flourescent lamp with horizontal straight tube, the bevel goes from "bright" to "dark" quite suddenly as you rotate the blade. If you can see a bright line at the very edge of the bevel, and the rest of the bevel is dark, the bevel is _not_ set. If you take it into sunlight, and hold it so that the sun would reflect off a section of dull edge, and you see a bright spot -- the bevel is _not_ set.

It is possible to shave off the 5 micron paper (which is _roughly_ 3000 grit), but not comfortable. If the film "bunches up" ahead of the edge, you'll ruin your work -- sticky film should cure that problem.

After 10-20 laps on a CrOxide pasted strop, the edge rounds _just a little bit_, smooths out a lot (it looks mirror-smooth under 10x), and the shave is pretty good.

My edges have improved since I got a Norton 4K / 8K stone (as everyone here recommended).

Charles

If the bevel is not set, then technically you don't have an edge. Going on from there will polish the sides of the bevel but have little effect on sharpening the edge you have not yet created. The reason bevel-setting is so important is that it establishes the edge which all the later work can improve. Without setting a bevel and the resulting edge, you are moving on to steps 2,3,4, etc. without completing step one. You cannot improve an edge that does not yet exist.

Originally Posted by cpcohen1945

If you can see a bright line at the very edge of the bevel, and the rest of the bevel is dark, the bevel is _not_ set. If you take it into sunlight, and hold it so that the sun would reflect off a section of dull edge, and you see a bright spot -- the bevel is _not_ set.
Charles

Originally Posted by ace

If the bevel is not set, then technically you don't have an edge. Going on from there will polish the sides of the bevel but have little effect on sharpening the edge you have not yet created. The reason bevel-setting is so important is that it establishes the edge which all the later work can improve. Without setting a bevel and the resulting edge, you are moving on to steps 2,3,4, etc. without completing step one. You cannot improve an edge that does not yet exist.

I understand. This is the basis of my question. I CAN see a thin white 'outline' of the blade at the cutting edge under low magnification (I use the eyepiece from an old 4x rifle scope) when looking at it from the side. Looks the same under my crappy microscope, and the rest of the bevel looks very flat. The bright line appears thick compared to the biggest scratches off the 5 micron film.

**Edit: but I CAN'T see any reflection if I look straight at the edge, only from the side like in the photo.

Obviously that tells me that the edge should be pretty dull, but then why does the blade pass all the other bevel-setting tests, up to and including shaving my face? I don't think it can be an overhoned or a wire edge. It looks the same on both sides and there's a very well-defined transition when the blade starts shaving arm and leg hair, after which I keep going for a bit and there's no noticeable change in sharpness when I backhone, strop or shave.