Based off my original design for my stapler but rebuild from the ground up with the intention of sharing an editable Fusion file so you can customize it the way you want. 

Designed around using 7g x 18mm cs screws as that is what I had laying around.

In this case I made one to hand my tape measure off the side of my workstation.

Printed in PLA, 0.20 layer height and 100% infill as a prototype. I'll probably reprint these in PETG just to avoid any creep on the parts.