wooden box help :)

[itssme]

You need a coping saw with a fine blade (inexpensive). Mark out the square hole on the side that will show and drill say a 1/4 hole within the waste area. Thread the blade through the hole and attach the blade to the saw so that the handle is on the rough side of the wood (side that wont show), with the blade cutting on the pull of the saw as opposed to cutting on the push stroke. Mount the workpiece on the edge of your bench (so that the cutting area is just off the edge with the handle facing the floor) and cut from the hole to just short of your line. Finish with a square file wrapped with garnet paper.