Clean the motor ends with a sharp knife. Use 8mm and 3mm drill bits to ream all of the holes. Use a 3mm drill bit to bore the hole all the way through the bar clamps. Clear all protrusions from the linking board mount tabs, using the knife like scraper. Do not bore the 8mm holes all the way through - just ream the hole with the drill bit!
Put M3 nuts in the nut pockets in each of the six bar clamps. With pliers, squeeze the nuts all the way into the clamp until the face of the nut is flush with the surface of the clamp.
Starting from the side opposite the nut, check that an M3 screw will thread in each of the nuts after they have been inserted in the clamps.
Insert two bar clamps in each of the three motor ends. Insert the clamps so that the round pocket aligns with the guide rod pocket and the nut aligns with the hole going through the clamp pocket.
Prepare six M3 x 16 screws with washers and put into the holes for the bar clamps. Just engage the threads, do not tighten the screw; guide rods will be inserted in a later step.
With the motor end laying with flanges down on the work surface, position a linking board so that its end is butted firmly against the end of the tab pocket. The board and motor end must be flat against the work surface. Start three #6 × 3/4" sheet metal screws into the tab and linking board but do not tighten them until the position of the board is checked – the board must be butted against the end of the motor mount tab so there is no gap between the plastic and wood and the board and motor end must lie flat on the work surface. Once in position, tighten the screws.
Repeat with another linking board on the other side of the motor end. A right-angle or stubby screwdriver will be required to engage some of the screws.
Continue with remaining linking board and other two motor ends. When complete, the whole assembly should lie flat on the work surface, flanges down, without rocking.
Put the pulley on the motor with one set screw lined up with the flat on the shaft. Leave a gap of about 5 mm between the pulley and motor. If the pulley has two set screws, use both of them!
Prepare twelve M3×12mm socket head cap screws each with an M3 washer. Stand the motor end assembly up on one linking board such that a motor end is facing upward. Carefully drop a screw with its washer into the motor mount holes.
Position the motor with the pulley facing up. The motor's wires should be exiting the motor towards one of the linking boards, not towards the top or bottom of the motor end. Start the screws into the motor but do not tighten until after all four screws have been started in threads.
Repeat with the remaining motors.
Choose the side of the hexagonal wooden base you wish to be exposed and place that side down on the work surface. Align the motor end triangle, flanges down, over the plywood base and with the linking boards over the longer sides of the hexagonal base. Align the base and secure it with six #6 x 3/4" sheet metal screws through the holes nearest the center of the hexagonal base.