Abstract: A self-centering bore hole gage includes a pair of centering points disposed on a guide block and a contact point and transducer disposed on a support block. The blocks are maintained in a biased apart relationship. The combination of biased apart blocks, points and transducer effectively self-center the gage in a bore hole so as to permit diameter and/or eccentricity measurements to be readily made by the transducer. The self-centering bore hole gage may include a plurality of measuring heads to simultaneously measure various ranges of diameter.