This is a first iteration drilling jig for the David Windestal Scratch Built Tri-copter.

It is designed to drill all the holes and slots you need.

The four holes close to the edges are to make the grooves in the 12mm, (.50") wooden boom for the shaft of the hardware to nest into, the one that seems to be in the middle, (clustered three) is to drill the one hole for each of the two forward booms.