Abstract: An arm-mounted motorized tattooing instrument includes a skin-perforating ink delivery wand configured for hand-held operation by a human operator, a wrist-or-forearm-mountable power supply, and a means for electrically coupling the skin-perforating ink delivery wand to the power supply. The instrument is configured to allow the human operator to operate the ink delivery wand without loss of power when rotating the ink delivery wand by hand about any of three orthogonal axes with the power supply mounted to a wrist or forearm of the same hand.