That's obviously no peace pipe, but a convenient tool to hold the nuts where they must go, such as these incredibly tricky corners and rod caps on the printers...
Update: I have added customizer support for your own needs (check the button above). I took the idea of opening the head laterally from peteruithoven (see derivations), thanks!
Spend 2 minutes printing this instead of getting nuts by losing them all everywhere :)
Default STL files are for holding an M3 nut. It is probably useful on all the printers that feature bolts behind pulleys in the corner of a frame, but also for your car or wherever you need to hold a nut in an uncomfortable position. Just use the customizer for all kind of variants (see the pics)
You can also make the handle very long, then bend it by heating it so as to curve it for trickier contexts even, it's probably easier than to redesign it.
The short STL files are for a standard M3 nut with 70mm and 110mm handles. Just make sure to use low extruding temperatures for the upper part when you print them. Your can also mount the nut on a long M3 screw, heat it and precisely thermo-form the hole if it's too tight. Handling it with a screw lets you pull it before it's too cold.
For other nut dimensions, check e.g. http://www.fairburyfastener.com/xdims_metric_nuts.htm
then use http://www.thingiverse.com/apps/customizer/run?thing_id=44118 to tune your own handle!
Update (20130918): added see-through hole to make pipe wrenches