# Iteration 4
## Did
- gen_carriage.py -> carriage_plate.stl (50x40x13mm, watertight): MGN12H block seat (4x M3 @20x15),
  slotted GT2 belt clamp ridge (2x M3), 4x M4 next-axis mount holes. Reusable on all 3 gantry carriages.
## Next
Start mobile_base.urdf (4-wheel base + vertical lift rail + arm mount) in docs/home_robot.