Geeetech single Z motor upgrade

*** Update 200521: please check out the remix by Peppered: https://www.thingiverse.com/thing:4377939 - it's awesome! ***
*** Updated 181214: Added stl for Nema 17 stepper. ***
*** Updated 180319: Added files for lower Z guide supports and the filament guide. ***

** Note: M@rkd0wn works whenever it wants to. Sometimes it looks ok, other times random text is bold and in a larger/other font. I can't control this. **

This design accomplishes three things:

• Keeps the Z-axis screws in sync

• Increases available torque (and speed, depending on chosen motor)

• Provides an easy upgrade path to proper lead screws, especially for the common T8x8

It is designed for the Geeetch i3 Pro B, but I suspect it will fit others as well.

There are three required prints and a few optional.
The required ones are the left and right top z mounts and a brace for the two belt idlers.
Optional: filament guide and lower supports for the z axis linear guides.

Things you'll need apart from the printed parts:

1 Bipolar stepper motor - Nema 17 or Nema 23.
1 GT2 852 mm belt, about $2 on ebay.
1 GT2 20t pulley for motor.
2 GT2 60t pulley with 8 mm ID for lead screws.
2 GT2 ball bearing idlers with 5 mm ID. I didn't have that, so I used ball raced pulleys.
2 T8 lead screws, 300-400 mm. 350 mm is ideal.
2-4 608 bearings (OD22/ID8/H7)
2 M5x30-35 screws
3 M3x12 screws
Perhaps some other screws, nuts and washers.

Optional:
1 M8 threaded rod, minimum 330 mm (used for extra bracing).
4 M8 nuts and washers.

Don't be afraid of the amount of text, this is really a simple upgrade.