Clamp four 1x4s together, mark the 15-degree angle along their edges and cut them all at once. Flip the bundle over and finish the cut from the opposite side.
2
Temporarily screw a 1x4 to your workbench and mark the cleat cuts. Set your saw to 15 degrees and cut the angles. Unscrew the board and cut off 5-in.-long cleats.
3
Center and screw the cleats to the 1x6. Predrill, then spread glue and screw the legs to the 1x6 and cleats. Keep the edges flush.