Summary

Each carriage need 4x 610 bimetal bushing
Smooth Rod diameter is 6mm

There is 3 model:

1. Smooth rod distance 60mm, arm distance 50mm
2. Smooth rod distance 54mm, arm distance 50mm
3. Smooth rod distance 49.2154 , arm distance 46mm

Each model have its carriage and belt pulley STL.

For Belt, it need to divide 7 or 8mm width into 3.5-4 mm width

The belt pulley need to use V624zz bearing

For arm end joint use 10mm plastic ball with hole.