Sharpening methods comparison

Home / Sharpening methods comparison - August 13, 2017 , by 54e8f7f6999ee8f9

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Rather than clutter up threads, I’m going to use this blog to keep track of my sharpening experiments. Let me know if there’s anything specific you’d like to see.

I’ll start with rehabbing a chisel using grinder, diamond, sandpaper, and leather.

Let’s start with a lowly antique store find:

I tend to prefer cast steel tang chisels, usually English ones. This one’s a Moulson Brothers 5/8’ish tang with a busted up handle, split short ferrule, and a rugged cutting end. Lots of pits and the sides are rusted and irregular.

I start by chiseling the handle off and examining the business end.

Now, this won’t do. It’s looking pretty rough. I’d have to remove too much of the back to get past the previous sharpening (wtf) and shallow pitting. Gotta Lorena Bobbit and get the tip off. I’ll just lob this one up for you: I’d rather lose some length than some thickness.

I always start with the back but I give a good look all around first. I don’t want to find deep pitting down the length of the blade and have to toss it with a well-finished back. I’ll push it over a diamond stone 20x passes or so and assess the highs and lows. If the cutting edge is distinctly low, as when dumbasses backbevel chisels, I’ll cut the sucker off and start fresh. In this case, I’ll start with the bevel to make sure I can establish a competent one.

I don’t own a surface grinder, so it’s a lot of work and staying true is difficult for me.I built this ugly grinder after getting fed up with my old bench grinder. It has too many stupid safety features.

I’ve got both the Tormek and JET wet grinders with all the trimmins but I prefer using this rig to set out the hollow grind, then establish the primary (the only angle for me) by hand. So I’ll start by coarse hollowgrinding to 29 degrees.

All looks good, so I’ll switch gears to the back. I want the back totally flat and polished, so I simply start coarse and then increasingly fine. The choice is in WHAT abrasives you choose. For this test, I’m going to use some coarse diamond stones (DMT) and sandpaper (AutoZone lol). I mount my sandpaper on marble window sills (Lowes, $15 or so) with spray adhesive (3M). This is a 10” extra coarse plate:

Pretty rough. I follow it up with the same stone in coarse. Then I move on to the sandpaper (Scary Sharp, they used to call it). I use water only to lubricate and try to clean off stray grit when I can. I’ve found one of those giant gum erasers meant to clean handheld sander belts works well for grime.

160:

220:

320:

400:

600:

800:

1000:
screwed picture up somehow

1500:

2000:

Looking over these micrographs, I few things jump out. I’ve got grit transferring from the previous sandpaper. I’m using more of a swirling motion than I thought. The ultra-high grits actually seem to continue to polish. I always figured anything over 1000 didn’t matter, but I did it anyway.

Now I want to establish my primary bevel, but I want to do it over my hollow grind. The hollow grind allows the tip to remain steady against the paper with less rocking, so it’s pretty easy to do this by hand. I have jig systems and I really like them, but they’re impractical for me unless I’m doing a lot of sharpening (which I rarely do). I’ve got a short piece of marble with 800 and 1000 grit paper. I can quickly sharpen the bevel and back and get back to work. I’m not good enough free hand so after a few intermediate sharpenings, when I’m approaching the base of my hollowgrind, I’ll quickly regrind and shape. I find the whole thing cheap, fast, and clean.

I start with a couple passes on a diamond plate to make sure that I’m getting full contact before and after the hollow grind (I’ve found chisels that were not even in thickness).

Looks good, so I’ll go through the grits, starting a bit finer b/c less metal to remove.

220

320

400

600

800

1000

Then I move to a charged leather strop for a dozen passes.

You can see that a wire edge starts coming off around 800 grit. We are removing veeeeery little metal and I couldn’t see it with the naked eye, even knowing that it was there.

It’s very difficult to take a picture of an edge but this one is very, very sharp. I never understood the “take the hair off your arm” test, as even a reasonably sharp blade will do that. You can gauge how many intermediate sharpenings you have left pretty easily. I could get more in the future by honing less initially, but my freehand skills aren’t there yet.

Totally finished edge.

Crap, gotta make a handle. Im feeling like a Ho. Ho-rmingo negro, that is. I like the shape of the Wm Butcher handle and I generally copy it, albeit a bit shorter with a stouter ferrule diameter.

I’m not the world’s best lather (I’m sure there’s a fancy word for that) but it’s standard stuff: pilot for the tang, shape the handle, finish with buttonlac and wax, and hammer it in with a bit of epoxy.

It turned out to be a pretty nice chisel. I’m a weird mix of conserve/replace. I don’t bother with metal aesthetics, just get the rust off. But if I can make it more comfortable, I’ll alter it. I usually shave bees wax into turpentine with a splash of BLO and put it on the windowsill for a week. I scrub that into everything in sight with 0000 wool. It’s like the perfect utility finish, preventing rust, affording minimum tack, and polishes up if you choose. Anyway, that’s all I did here.

I can see myself reaching for it. Next, I want to do basically the same thing with water stones. The winner will get the same treatment using jigs, etc. I’d also like to look at Tormek and charged honing wheel alone. Thanks for looking!

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