This is a customizable clamp for mounting a laser diode (or other cylindrical objects) on an optics mounting post. The default STLs are for a 12mm diode on an 8mm post with M3 bolts and nuts.
This component was inspired by the Open-source optics project, whose goal is to radically reduce the cost of scientific optical hardware, by the Michigan Tech's Open Sustainability Technology Research Group.
UPDATE: now slightly smaller, using measured sizes (and some leeway) for the nut to reduce slot size. And tighter on the post/rod.
This prints well at 0.2mm layers or finer, and I didn't need supports on my printers.
PLA works, but is fragile (don't over tighten!). ABS works better, but may not be compatible with some plastic diode housings. My Acrylate test broke pretty quickly, but could vary depending on the material flexibility. Sintered nylon is almost too soft, but still works. Of course, if the material is too flexible then the clamp won't hold the diode in place.