A method and apparatus for moving an article relative to and between a pair of distance sensing probes of a thickness measuring apparatus which are spaced apart a known distance D is described. In the method, the article is moved relative to and between the pair of probes in at least one direction in a plane normal to a common measurement axis Ac between the probes. From the measured distance a, the article is moved relative to the probes along the common measurement axis Ac so as to minimize any difference between the measured distance a and a desired distance ad along the common measurement axis Ac between the first probe and a point on the surface of the article nearest to the first probe that intersects the common measurement axis.