Leonardo da Vinci carried out some of the very earliest experiments on friction and wear.
Da Vinci deduced what we commonly call Amontons laws of friction, or Coulomb friction, that is, that friction is independent of area and directly proportional to the normal load.
He carried out some wonderful experiments on the wear of axles and shafts, demonstrating the shapes that would be formed as a wooden wheel wore against an iron axle.
Leonardo's notebooks contain beautiful sketches of machines and devices, including designs for bearings, screws and gears; all of which can be found in most modern day machines.