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:

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:

Then I saw a kerf down the length:

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

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.

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

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:

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

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.

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.

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

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.

I’ve Got an Axe Inshave to Grind.

There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man’s lawful prey.

-John Ruskin

Okay, so we established in the previous post that my new inshave is a bit of a disaster. But I’m an optimist and remain hopeful that I can turn the depressing collection of bent steel and varnished Asian hardwood into something that actually resembles a functional tool. The work begins at the grinder. First step is to take an edge that’s wavier than the Pacific coast and make it passably flat.

I always start any major grinding work by grinding the edge to 90°. There’s a good reason for this: you want to avoid creating a sharp edge for as long as possible, so the steel doesn’t heat up so quickly and ruin the temper. It also creates a guide and makes it easy to see where you need to focus your efforts when grinding the bevel.

Tool rest omitted for clarity. Please don’t try to grind your blades without a tool rest. This isn’t like a woodworking magazine where they show a tablesaw without the guards and say “Guards removed for clarity” but you know damn well they never even put the useless things on.

You don’t need to overdo it here. Just grind the edge down until the high parts are in the same plane as the low parts.

Before

After – not perfect, but close enough.

You can see the “flat” created along the edge. It’s thick in the middle, where most of the steel was removed, and narrow around the corners, which started out as low spots.

Next, I drove a nail into my tool rest which functions as a bastardized version of the fancy-pants grinding jig that Peter Galbert wrote about a few years ago.

A quick look at the edge shows that the nail jig is located correctly. The stone is grinding right in the middle of the bevel, which will maintain the original grinding angle.

Now that the nail jig is properly located, the painstaking work of grinding the bevel begins. There is a lot of metal to remove, and a deft touch is required to avoid bluing the steel and ruining the temper. It probably took almost an hour of grinding, checking, and grinding some more until I was finally happy the the results.

An hour later, and all is right with the world.

The grind is even and there are no screwy waves and dips in the edge.

The hardest part of the process was getting a smooth grind around the corners. The middle of the blade was no problem at all. I haven’t used this technique on a drawknife, but it was easy to tell that it would work beautifully on a straight edge.

Up next: I still need to polish the back of the blade and hone the bevel.