"Duncan Dowson pointed out, the wear of a metal on metal bearing needs to be
kept in perspective. He taught us that the wear experienced by a metal on metal
articulation over 15 years of use equates to the volume of one pin-head (Fig. 31.3
). Fig. 31.2. Rig to feel the frictional torque of different bearing couples. (Image
supplied courtesy of Mr. Martyn Porter, FRCS, and the Wrightington museum). Fig
. 31.3. From a lecture delivered ..."