56 Bottles of Beer on the Wall

Last weekend I made good progress on the front and back of the crib. These two parts are similar in that they both consist of cherry rails connected by a number of curly maple slats. How many slats, you ask? 14 -- on each side. That's a total of 28 slats, and each one needs two mortise and tenon joints (for the top and bottom.) So, that's 56 mortise and tenon joints to cut.

56 mortises is a job for a dedicated mortising machine, which performs the magical task of drilling a square hole. I bought this machine a while ago because I got sick of cutting mortises with a router, which requires a complex jig and results in a rounded mortise. A bench-top mortiser is essentially a drill press with a special hollow chisel bit that attaches to the head. Inside the hollow chisel is an auger bit that drills a circular hole -- the chisel on the outside squares up the hole.

Even with the mortising machine it takes a while to cut 56. The third picture shows the four rails, each with 14 mortises. The narrow rail is the top and the wide rail is the bottom. The wide rails will eventually be cut with a curve, but it's easier to clamp the joint before the curve is cut.

The next step is to cut tenons on each of the slats. Again, we've got 56 joints to cut, so it needs to be efficient. I could have used my table saw tenoning jig, which produces very nice tenons, but would take forever. Instead I set up the table saw with a dado blade, which is much faster, but cuts a fairly rough tenon. The last two photos show one mortise and tenon -- not a bad fit!