Abstract: A machine guard safety gauge is a single piece made up of a series of stepped cylinders having diameters equal to a maximum safe opening size from a hazard zone of a machine at corresponding combined lengths from a tip portion of the gauge. The centerlines of the cylinders share a common vertical plane and the cylinders share a common bottom edge. This design provides three dimensional structural stability and strength which allows the gauge to be used for both checking and setting up machine guards. A tapered tip design allows checking the positioning of abrasive wheel adjustable tool rests, tongue guards, and "nip points" in general.