About this 3D model

Ball bearing supported pen holder to scratch pcb. The Idea is to scratch a layout on a coated pcb and etch afterwards. It is described by some other guy already http://reprap.org/wiki/Scratch_n%27_Etch_PCBs. I have printed it but not jet tried to use it. Since the print was disrupted the tube in the image is a bit shorter and the Plate on the end is not perfect aligned.