The lab needed to attach a portable webcam and a portable projector to pvc pipe, so I designed these models.

I started with making the camera attachment with Autodesk Inventor (it needed to be printed almost solid because the camera insert portion was so thin). After a few trial and errors, I got the right size to slide in and out of the pvc. The flatten edge was made to make it easier for printing, and for insertion and removal. The tolerance is decent enough that the friction force works pretty well.

Later, they asked me to make a similar attachment for a projector. So I recycled the pvc attachment, and a standard camera screw model to create a quick fix on in OpenSCAD.
Be careful, you do NOT want a plastic screw to break off inside your device. It can be difficult to get it back it. When in doubt, make the model thick and strong enough that it won't break.