These are some of the patterns made to manufacture drawing instruments one to three. The following four types of instrument are made on laser cutters (and the subsequent ones have reverted to aluminium using a waterjet cutter). The patterns are made of cibatool, a homogenous and isotropic material designed to have no variation in character and to machine easily. I cut them on my small cnc mill.
The pieces of wood are added as air vents when making the silicon rubber mould so that whatever is poured into them can displace the air in the void. The parts for drawing instrument one were cast in plastic and for instruments two and three (and the incomplete instrument) in aluminium. For these I cast wax into the moulds that the foundry covered with a ceramic case and then melted the wax out to make the mould for the aluminium.
Pattern three (above) was the first piece I machined. There are no drawings of the whole thing and no complete drawings any of the parts. They were designed incrementally, even within each part, so the only thing known about the next component was the dimension and geometry of the fixing to the previous piece.