The repeatability of contact-gauge probes against engineering surfaces

Growing demands for micormetre-level capability in factory-floor metrology lead to the need for greater understanding of the contact behaviour of probe tips onto engineering surfaces. We report here on the first stage of such work. A simple testrig suitable for determining the parameters for later detailed study is described. A lever geometry is convenient but has inherent errors that are discussed. First results show that even on ground steel workpieces uncertainty in probe indentation is, at this level, a non-negligible factor in the error budget of displacement gauges