OpenSCAD code included for modifications. Just print on your favorite open-source 3D printer and clean up. You will want to flip the stl for easy printing.
You'll need an M3 Nut and screw. Put the screw through the rod holder and screw onto the OpenBeam with an M3 nut.
You can get Open Beam at http://www.openbeamusa.com/Extrusions/
This project was developed by the Michigan Tech Open Sustainability Technology research group http://www.mse.mtu.edu/MOST
Thanks to Terence Tam for Open Beam.
This component is part of the Open-source Optics Library: Zhang C, Anzalone NC, Faria RP, Pearce JM (2013) Open-Source 3D-Printable Optics Equipment. PLoS ONE 8(3): e59840.
This is part of a larger project to reduce the cost of scientific equipment using open-source hardware. Read more here