Spider coupling - 5mm axis to M8 drivescrew

This is a printable spidercoupling. It connects a stepper with a 5mm axis to an M8 drive screw. Both parts are uploaded below as separate STL-files.
You will need 4 M3x10 bolts + nuts to finish the part.

This thing is part of a design for a small CNC milling machine.
More details can be found at http://www.repairablemachines.com