I can't seem to get my hands into some of the tiny places to hold onto a M3 nut to tighten down the screw. I saw a few 3mm wrench's for sale on line, then I realized I have a 3D printer and google sketchup. I made a few versions but this one seems to work the best for me.
I am not yet up to learning new design software, so I am only able to offer the STL file.
As usual, if this thing already exists then please accept it as my version.