Back in February I got this small incannel gouge at a tool show. I cleaned it up and sharpened it at the time, but I didn't really put it through its paces until recently. When I sharpened it, I knew something wasn't right. I just couldn't seem to get a good consistent edge. It sat on a shelf until this week waiting for me to look more deeply into it.
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| New Haven Edge Tool Co. |
The curve of the gouge is part of a 9/16" diameter circle (9/32" radius). The cutting edge measures 7/16" corner to corner. The handle is clearly a user-made job, and it had come loose while I was working on it, so I made a new one.
When I tried sharpening the gouge, something wasn't right. The wire edge that forms would get too large and end up flaking off more metal than it should have. One time, when I finally got a good edge, I tried to cut some wood and the edge just crumbled.
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| Result of using the gouge lightly. Can you see the chip in the edge? |
I figured the tool had lost its temper somewhere along the line. So I annealed it by heating to cherry red and plunging into a bag of vermiculite to allow the heat to dissipate slowly.
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| My heat-treating set-up: two torches pointing at a steel can. The gouge is stuck in the vermiculite at left. |
After it had cooled, I hardened and tempered the gouge. This was the first time I tried to temper a tool by watching the color advance towards the cutting edge. When the edge got to a straw color, I plunged it into oil to stop the tempering.
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| You can see the colors here on the convex side of the gouge |
After cleaning up the blackened and discolored steel, I gave it a good sharpening. But I got an equally crumbly edge! I'm aware that when heat-treating an edge tool that has a sharp edge, the thin cutting edge can get overly brittle. So I ground back a couple of millimeters and re-sharpened it. This time I finally got a good cutting edge without crumbling. I tested it on some end grain walnut and finally didn't ruin the edge after just a single or even multiple cuts.
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| Testing on end grain walnut |
When I was satisfied that the steel was in good enough condition to warrant a new handle, I got a chunk of cherry, sketched a pattern on some cardboard and got out the bungee lathe. The shape didn't come out exactly how I had planned, but it'll be fine.
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| Showing the new handle and the lathe set-up |
This was my first time re-handling a tanged tool. To fit the tang into the cherry handle, I drilled successively bigger holes at successively shallower depths. I had to adjust the hole a bit to get the gouge to align better with the handle. I used the brass ferrule from the original handle, which had a 5/8" outer diameter and just shy of 9/16" inner diameter. It was very satisfying when I tapped the handle home up to the bolster.
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| New handle next to the original |
I gave the handle a single coat of BLO, which really brought out the color of the cherry. Another tool in the arsenal.
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| Completed |
