Attached is a picture whose only purpose is to show that I am actually doing something. Doing it badly... but doing something.
This is Brian's Bellows Board B which doesn't have much going for it beyond alliteration.
You can see that the slot in the side isn't exactly straight. I made it by drilling 3/8" holes 4" apart on the drill press. Then slipped one over a 3/8" bit on the router table and slid it along till I got to the other. I took several passes, raising the bit each time, till I got all the way through. Only, the drilled holes wound up being a smidge wider than the slot. Not quite sure why. I'm thinking the fence on the drill press isn't square to the table. I sanded it down to make it look a little better. It's still not perfect, but it's better in person than it looks in the picture. The light is reflecting off the edges kind of funny.
Also, I haven't put the bottom on yet. That's because the plans say to round the edges of the holes on both sides and I haven't done that yet, because I'm not quite sure how to do it. Best method I've come up with so far is to roll up some 220 sandpaper into a tight cylinder and go at it that way. It works... but there's a total of 39 holes. That's going to get awfully tedious. I'm kind of hoping there's a faster, easier way to to it.
You can't tell from the picture, but there's also a tiny little twist to the board. If it were sitting flat on the saw table... well, that's just it. It wouldn't be sitting flat on the saw table. The front right corner would be maybe 1/32" off the table. I hoping that'll go away when I put the other side on.
If it doesn't, I just might start over.