coupler trapezoidale T8

coupleur trapezoidale (T8)/5mm(motor) customizable

update 2018-08-02: (final version)
- fix hole nuts
- fix hole t8 and axis motor

update 2018-08-01:
- added a delta for the retraction of filament for hole.
- files .scad uploaded to calibrate and customize.

The lib threads.scad you can download here:
http://dkprojects.net/openscad-threads/

threads.scad is a librairy of the T8, put this in same folder of other .scad

There are some file to determine the delta, (retraction of filament) to adjust the hole to the reality