Instrument for measuring internal dimensions

摘要

An instrument is disclosed for measuring internal dimensions by effecting an absolute measurement of an internal dimension of a workpiece using two measuring elements. This instrument for measuring internal dimensions has probes of the measuring elements disposed at two points on a plane incorporating the center axis of a positioning member, the forward end portion of which has a tapered surface, and the probes are adapted to abut against the inner wall surface of the workpiece which is guided by the tapered surface of the positioning member, whereby a distance between the two probes in the aforesaid abutting state is detected by a displacement detecting device, thereby measuring the internal dimension of the workpiece.