Z-Axis holder for 20x20 (v-slot) Axidraw style DrawBot

For a DrawBot, or Axidraw, made with 20x20mm profile V-Slot aluminium extrusions, this part serves to join the drawing arm to the pen holder and allows the timing belts to be secured tightly while holding the unit in place. Uses standard dia 4.5mm bolts on 20x20 profile drop-in nuts.