Our first process is to get the bottom joined to the sides. We’re going to use dovetails for this joint. The problem I have with that is in scribing my knife lines. My combination square is too short to register solely from the reference edge, and I don’t want to introduce the possibility for error by squaring off both edges. I can, however, use my framing square to scribe this line. Keeping everything together while knifing (and not moving anything!) is troublesome at best, so I use my handy quick clamps to hold the square while I scribe.
Now to cutting the dovetails! Once the base line is scribed, I’ll go ahead and saw the joint with my trusty Disston 12″ hybrid saw, starting with tails, then superimposing them on the other board to make the pins.
Keep these dovetails relatively beefy. We don’t want to pull a gossamer pin out by the root. Also, construction detail here: MAKE SURE to orient your dovetails so that the tailboards are the sides. This puts the mechanical locking properties of the joint in line with the stresses this shelf will encounter. If you do it wrong, the only thing holding the bottom on is the glue and that’s insufficient.
All joined! This post brought to you by a giant letter “U”.