5.5mm hex nut driver for use with the OpenBeam system.
Notice that lots of projects are starting to use more metric hardware? Even in the USA (one of the staunch metric hold-outs), projects like Makerbot are using metric hardware in their designs. Look, we're not here to debate which is the better engineering unit (coughthousandthscough), but to show off a new tool!
We're carrying the open-source kickstarted "OpenBeam" construction rails, and this is one of their tool accessories. This 5.5mm hex nut driver features a KraftForm handle for improved ergonomics. Ever use a nut driver? WOW, it really speeds up construction over the use of a open-end wrench! It's like a compact, tiny socket head permanently mounted on a screwdriver hand, but since the nutdriver shaft nutdriver is hollow, it can drive nuts down onto a stud up to 120mm long!
The 5.5mm size hex nut is a German DIN standard; however, most metric sized wrench sets do not contain a 5.5mm socket. If you are going to be doing a lot of work on the shaft clamps or motor mount brackets, it'd be a good idea to pick this up. OR, you can use a 7/32" wrench, which will fit on a bit sloppy, but do the job. But it's still best to use the proper tool for the proper part!