Abstract: A direct reading radius gauge includes a Y-shaped frame having a base and two divergent legs, and a micrometer head having its spindle arranged to penetrate an opening provided through the frame base portion. Values are imputed to the cooperative scale elements on the micrometer. The micrometer is calibrated to indicate zero when the spindle end face includes the line of intersection between two facing convergent planar surfaces on the legs. When the leg planar surfaces and the spindle end face contact an object's surface of revolution, the micrometer scale will indicate directly the radius of such surface.