Motor mount Fig. shows images of the motor mounting assembly with (b) and without (a) the motor in place. As the motor diameter is larger than the optical cage, we use a pair of 7 mm-thick 3D-printed plates joined by three 6-mm steel rods of length 55 mm to obtain an expanded section of the optical cage that is large enough to accommodate the motor. The motor plates are identical, except for the inclusion of 3.2 mm holes (sized for M3 screws) in the left-hand plate to secure the motor. The plates are printed from PLA at 100% infill for maximum durability, and are fixed to the optical cage using M3 set screws that self-tap into pre-formed radial holes in the plates. The 1"-diameter polariser P3 is attached to the motor using a 3D-printed ring-mount and two M3 screws, which engage with pre-threaded holes on the motor bell (see Fig. ).