After I posted about doing my first hand-cut mortise and tenon, Scott wanted to see how I chopped my mortise. He said, “The only time I tried to chop a mortice I left most of a 1/4” chisel broken off in the wood.” Well, when I read that, I kind of freaked out because I hadn’t considered that I could have broken my blade! But I decided to trust in what I was taught, and to remember that I had, indeed, done one successfully. So I decided to keep at it for my second mortise.
First, I marked out the mortise. I figured out where I wanted it, and then measured the top line with a pencil (exactly 3” down from the base of the pins). I marked that spot with the chisel by pressing it firmly into the wood. After measuring the height of the tenon, I did the same thing on the bottom. Then I connected those outer borders with a marking knife:
I then positioned the chisel slightly in from one of the edges, with the bevel facing the other direction.
Next, I raised the chisel to 90 degrees and gave it a good strike with the mallet. I levered the waste out by lying the chisel down toward the bevel. Here’s a pic:
And here’s the video of me doing it:
After going the whole length of the mortise, I turned the chisel to face the other way and went back, doing the same thing. Then I flipped the board over and started on the other side of the mortise, doing two passes. Before too long I punched through:
At this point, it’s probably safe to hog out the waste by chiseling down the side walls, although I just kept going as I was, ending up with this:
You notice that the side walls need to be cleaned up, and also the length of the mortise extended all the way out to my marked lines. In the next pic, I’ve cleaned up the sides and just needed a little more on the top and bottom.
And there’s my mortise! You can see in the last pic below that it’s far from seamless perfection. But considering that the tenon will be wedged, and that decent-sized dovetails are securing the sides to the top, I don’t think this joint will experience much stress.
Thanks for following along!
-- Eric at http://adventuresinwoodworking.com