• 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.
The author marked this model as their own original creation.