Push Drill with Adjustable Chuck

Inspired by Speedy777's Pump Drill (http://www.thingiverse.com/thing:731086, which was inspired by Performance 3D's drill), this slightly beefier version features an adjustable chuck that can handle bits from 5mm (3/16") down to 1.5mm (1/16"). The end of the bit seats in the conical shaped chuck cavity, and the flexy fingers at the tip grab further up the shank. You get 2 full rotations per stroke for fast drilling. It also works as a pin vise for holding needle files.InstructionsUpdate: I've uploaded a new version of end_nub.STL which should fit better.All parts were printed in PLA with 3 perimeters and 30% infill. The drill body was printed on end with 0.2mm layers - you may need a brim. The slider, chuck and end nub were printed with 0.16mm layers. The difference in layer height keeps the layer-line ridges from lining up with those on the drill body and makes for smoother operation. Note that the chuck threads may need a little cleaning up with a triangular file.To assemble, first p