Measuring location sensor for linear measuring devices

A linear measuring device for measuring the location of a round hole in a surface inclined at an acute included angle to at least one of three mutually perpendicular coordinate axes, comprising, at least one measuring beam constructed and arranged to extend longitudinally and be supported in a substantially horizontal plane, a carriage slidably mounted on said beam for movement longitudinally thereof along a first axis, a slide mounted on said carriage for movement therewith and along a second axis perpendicular to said first axis, a probe assembly removably carried by said slide for movement therewith and having a probe which can be extended and retracted relative to said slide along a third axis pependicular to both said first axis and said second axis, a spherical tip received on said probe for movement therewith and having an outside diameter greater than the inside diameter of the round hole in the inclined surface, a measuring scale carried by said probe assembly and calibrated as a function of the outside diameter of the spherical tip and a given inside diameter for a round hole, and a housing removably received and seated in said slide for movement therewith, said probe being telescopically slidably received in said housing, said spherical tip being removably received and seated on said probe, and said scale being caried by said probe for movement therewith relative to said housing.