moon's bolt - yet another hobbed bolt

Here is the hobbed bolt I have been using for the last 10+ months with better results than anything else (check also the complete feeder at http://www.thingiverse.com/thing:73082). Time to share!

Though it looks like "old school", it is extremely reliable and could prove useful to makers that do not want to buy expensive machined bolts, or that build their own filament feeders or extruders.

As for me it compares favorably to MK6 and ultimaker drive bolts. Grinding and slipping is something