All kind of V-slot rail customizer.
Also a .scad library include
V_slot("shape",lenght);
shape=[20x20,20x40,20x60,20x80,40x40,C-beam]
ex: V_slot("20x40",53.2);
• Download and install latest version of Openscad here. This is an opensource light software (21MB).
• Download the *.scad file and open it with Openscad
• Play with the values in the customizer panel (if it is hide go to view/hide customizer)

• Once you find the value you want/need, press F6 to render…and then F7 to export as STL.
Der Autor hat dieses Modell als seine eigene Kreation gekennzeichnet.