Furthermore I enjoyed working with round saws of 20 to 75 mm intersection for passages of pipes and wires in wood and metal. To use these saws I had to use a more powerful drill, not only because of the power, but also because you need a larger opening to connect the saw. Furthermore a rivet nut plier is indispensable (see references). Starting with this project I had no idea of even the existence of this device. Nuts are connected to tailored holes in the ribs with this device and with the appropriate screws plates or beams can now be connected to the ribs. A flat screw head is most suitable. Important is to make a print of the position of the nuts onto the wood, to drill the holes for the screws in the proper places. This is subtle work and can go wrong.