This is a rework of barspin's Fully assembled 3D printable wrench. I had a hard time slicing his in slic3r. It was merging some of the parts together. Even his 'more gap' design. Also, I have a printrbot jr so my bed is fairly small.
This stubby version has a slic3r sliceable head and a nice stubby handle. Printed well, and the built in support came out easily.

Slice, .2 is nice. More infill makes a sturdier wrench as does more perimeters and shells. Print without support. Remove support bits. They pop out. Then wrench!