Now there is an operational prosthetic hand on Thingiverse called Robohand, uploaded by the men behind the ‘coming up short handed’ project (VIDEO)
Richard Van As cut the four fingers off of his right hand when he was using a table saw a little too quickly one afternoon, trying to make deadline on a client’s piece (he still delivered quality work). After painfully wrapping his hand and awkwardly stuffing the two of his fingers that he could reach into his apron pocket, he went to the emergency room, and after seeing his hand unwrapped and mangled, he told himself that he would build himself new fingers. Mechanical ones that work, not merely some static mannequin hand to hold his wedding ring. He did a bit of research, which generally lead to ridiculously expensive prosthetics, except when he stumbled across a video of a man showing off a mechanical hand that he built for a costume.
Source: 3D Printer