NEMA-11 stepper driven linear stage

This is a work in progress, but already working.
I attach the parametric designs (currently compiled for a NEMA11) that permit to couple a stepper motor with a linear stage (in my case, a Newport M-UMR8.25).
http://www.phidgets.com/products.php?category=23&product_id=3300_0
http://search.newport.com/?x2=sku&q2=M-UMR8.25
I provide two versions of the shaft coupler:
* Shaft.stl: direct coupling, need fine polishing touches and alignment
* Shaft2 - a, b and c: articulated coupler (prefe