Still not completely happy but this is big improvement.I went back to my original design (http://www.thingiverse.com/thing:2537) and cut out everything that wasn't actually doing something.Then I oriented the pieces so that nothing would press along the "layer" lines so hopefully this will be a stronger than my previous design.I think result is cleaner, I know its smaller and will use less material, with any luck however it will prove more useful and durable.As usual the SKP file is included for anyone who wants to enhance, adapt, improve, etc.Updated (v4): Overhang corrected Battery end tabs merged Battery end tabs moved to increase grip Extra holes placed to ease contact positionsThis design is untested.1 STL = 2 parts - Either screw or glue in place.stiff wire is pushed up through holes in the base and hooked over the springs to for the contacts.