I wanted to have a go at making a "one print" design of a pivoting ball locking device. Here's what I ended up with. I tapped the holes with a 1/4-20 tap. Use the obvious orientation when printing. I haven't tried to correct the orientation issue yet. May need to be scaled depending on which slicer is used. I use Simplify3d, so when I open the STL file it asks me if I want to scale it accordingly. I may make more variations at some point.

Note: A standard tap didn't work for me, so I ordered a bottom end tap to see if it works. Also this could prolly be scaled a bit to work accordingly.