Sow’s Ear, Meet Silk Purse: Sharpening a Very Bad Inshave.

In our last installment of The Very Bad Inshave Saga, I demonstrated a simple way to get a nice, consistent grind on the bevel. It took plenty of time and patience, but the results were satisfying. I’m not out of the woods, yet, though: I still have to hone the bevel, and I haven’t even mentioned the condition of the back, yet:

inshave (9)
It’s bad. It’s really bad.

Since a sharp edge is nothing more than the acute intersection of two polished surfaces, I’ve got to get the back polished before I can hope to make this tool sharp. Right now, it’s a long way from polished. I started by turning dowel about 1 1/2″ in diameter on my lathe:

inshave (10)

Then I saw a kerf down the length:

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And fit a quarter sheet of 180-grit sandpaper into the kerf:

inshave (12)
One tip: Sandpaper that is worn out from sanding wood can still have some life in it for abrading metal.

Then, I turn on the lathe and carefully work the entire edge, being careful not to round over the back of the edge too much. This is a more delicate process than it appears; you can do a lot of damage in a hurry, so be careful.

inshave (15)

After a couple minutes of work, I pull the inshave off for inspection:

inshave (17)
It’s getting there, but there’s still work to do. The polish has to reach right up to the edge, all the way across.

I continue with the 180-grit until I have an even shine, and then I work the blade up to 600-grit to give it a nice polish:

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After 600-grit, I charge the dowel itself with some green honing compound to get a mirror shine:

inshave (1)

And that’s it. The back is polished, and it only took 20 minutes or so. Now I can turn my attention to the bevel. Honing the bevel of a curved edge is always difficult and requires a fair amount of skill, but I found the shape of this inshave to be particularly hard. There is a lot of metal here – far more than a simple carving gouge – and besides that, the uneven curvature of the blade means that I’m constantly having to re-position my stones as I move along the blade. I’m not so sure I could have done this were it not for the hollow grind left by the grinding wheel.

I started with a 1000-grit slipstone, honing along the bevel, not across the bevel. I followed it up with a 4000-grit slipstone and a bit of stropping with honing compound on leather. The polish on the bevel is tiny – too small for me to photograph, unfortunately. Only the very edge needs to be polished.

inshave (4)

I was not able to get this inshave to my usual standards of hair-popping sharp, but I did get it sharp enough to easily slice through sassafras. I found that I could hog off thick chips, or very fine ones – the tool is surprisingly responsive.

inshave (5)

And it leaves a beautifully smooth surface. I think I’ll have no trouble going straight from the inshave to a scraper.

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So, there you go. My tool-making escapade for the Windsor chair is nearing completion. I still need to build a shave horse, but the number of excuses that I have for delaying the project are steadily dwindling.

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3 thoughts on “Sow’s Ear, Meet Silk Purse: Sharpening a Very Bad Inshave.

    1. Thanks for the encouragement, Dave! I’m just getting started, but glad you’ve enjoyed it so far. Sharpening curved tools is the final frontier for me.

      I feel like grinding the bevel and polishing the back were the easy parts, but I’m not completely happy with my stone work on the bevel. I feel like oilstones would be preferable, but I’m stuck with my waterstones for now, which seemed a bit too soft. I’d be curious to know your methods for sharpening an inshave/scorp.

      Like

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