Abstract: The present invention provides an inexpensive device particularly designed so as to permit easy, accurate adjustment of the working edge, edges, surface or surfaces of the movable head on any of a wide variety of mill and shop tools. A housing encloses a battery and number of spaced electrical contacts, so arranged that a circuit through a light-emitter and a sound-emitter is made only when one of the electrical contacts engages a fixed-location site on the tool and another engages a working edge or surface. In this way the working edge(s) or surface(s) may be adjusted so as to just touch the contact which sets-off the light and sound. For versatility there is more than one of these working edge or surface-engaging contacts, variously located on the device for alternative use. A special housing shape is disclosed as is the use of permanent magnets for holding the device at a uniform location for certain uses.