Hand Tools

Subject:
Yet another chisel edge test *PIC*

Winston
Many of my previous posts focused on pictures of what a chisel edge looks like with different treatments, but this time I did a controlled test of chopping, similar to what David has done. The short version is that the edge durability that I got was extremely impressive -- better than I thought I would get.

Note that I've put this information plus a lot more pictures at https://chisel-chop-test.netlify.app/. There are pictures of the edge as the test progressed, so you can see how the edge gradually gets damaged. Well, you can see how the flat-sharpened edge gets damaged. The buffed edge looks essentially unchanged throughout the test. Please bear in mind that the content there isn't permanent; it will change in the future as I test out more things, and the URL will change as well.

For these tests, I used a 3/4" Buck Brothers chisel from Home Depot. At $21 for a set of three, this is a cheap chisel. In the past when I've used it, I've been kind of surprised at how quickly the edge gives out. I don't think it's a bad chisel for the price; it's that just I've gotten used to my nice chisels.

I compared this chisel with two sharpening methods. For the first test, I used a flat 30-degree bevel, sharpened up to a 12000 grit Shapton Pro stone using a honing guide. For the next test, I sharpened it with a 30-degree bevel on a 1000 grit Shapton Pro, then I buffed the chisel for about 10 seconds using a drill with a 4" spiral-sewn buffing wheel and white rouge compound. I also ran the back of the chisel on the side/corner of the buffing wheel (avoiding the buffing compound) for about 1 second to remove any possible burr. (An aside: I find that I have to charge the buffing wheel fairly frequently, like every few sharpenings. Also, I don't claim that the white rouge is the ideal compound to use -- it's just the first compound I used, and the finest, so I've been sticking with it for now.)

I chopped a 1/2" wide, 3/4" thick piece of soft maple 20 times, taking off a 1/16" slice each time. Here's what the chopping test looks like:

The "edge" images below are taken looking straight at the edge, with the back of the chisel parallel to the axis of the lens. You can see the bevel in the images, but the reason you can't see scratches is because the depth of field with the microscope is so shallow, so they're blurred out. The edge-on images were taken using a 45-degree mirror under the scope, with a small light held in the same plane as the chisel back.

Here's what the flat-honed chisel looked like, with views of the bevel, back, and edge. It's not the best edge I've gotten off of the Shapton 12000, but it's probably representative of when I'm sharpening normally and not putting in the effort to get a perfect edge.

And this is what the buffed (AKA unicorn) chisel looked like:

This is the flat-honed chisel looked like after chopping off 20 pieces:

And the buffed edge after chopping off 20 pieces:

This is a huge, huge improvement over the flat-honed chisel. There is essentially no visible damage to the chisel, even with the microscope. I swear that I actually did all the same chopping for both test runs. I can tell by feel and by shaving that it's not quite as sharp as it was to start with, but we're talking going from extremely sharp (able to cut hairs without contacting skin), to just really sharp (able to shave hair just fine).

This is a picture of the profile of the chisel. There's a part that looks like it's hooked below the flat back of the chisel, but I think that's just an artifact of the lighting.


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