Friday, January 22, 2010

Call Me Ishmael

When it came time to move my tools from my old shop in the basement to the new freestanding shop, I took a careful look at each tool and the role that it played in my work. I wanted the new space to be uncluttered by tools that didn't pull their weight in the work that I do now. Many decent tools didn't make the cut, and stayed on the shelf in the basement.

When I made the move, none of the chairs that I made had square mortises, so the mortise chisel that I picked up at a shop on Cape Cod in 1997 has gathered dust for years, even though I knew it was a beautiful tool. I had even taken the time to put a new handle on it, which makes it look like it belongs on an old whaling ship (I have no idea what I was thinking with the copper).

The chisel is made with a laminated piece of high carbon steel and holds a great edge. It's shown here with the smaller chisel that I use to clear the chips.

Recently, I was looking online for a 5/16" mortise chisel, when I remembered my shelf of dusty tools. There it was, but to my dismay, it was 3/8" with a tapered cross section. Now according to the stuff that I've been finding online, the chisels that are tapered away from the full thickness like this are preferable, but I've always found that square chisels track in the hole better and don't tear up the sides.

So you know where this is going, I ground the taper out until the chisel was rectangular in cross section, probably destroying any collector value, but to me making it a tool worth ascending to the new shop.

Here's the wall of the mortise, I had trouble getting this clean a result when the tool was tapered.

And here's the chisel sitting in it's own hole.

Now that it's performing so nicely, I even cleared a spot for it on the wall behind my bench. Welcome back Ahab.


Anonymous said...


Are mortice chisels always sharpened with that radius-ed back edge?

Do you prefer it?

I can't tell if it seem like it would be trickier to sharpen, or falling-off-a-log easy to do.



Peter Galbert said...

The mortise chisel needs a great deal of support behind the cutting edge, so I don't hollow grind the whole width of the chisel, which would make a very thin leading edge. Instead I round the bevel and then hollow only about half the width. If you look closely at the images, you can see that there is a flat portion leading up to the cutting edge. This is the best compromise that I've come up with between being able to sharpen consistently and retaining the mass,
thanks for the question,