Dry bearings

Dry Bearings are the simplest and most convenient method of lubrication. However any bearing surfaces based on dry lubrication will progressively wear during relative movement. Dry lubrication is ideally suited for the following applications:

  • Coating threads to prevent seizure and enable release
  • Coating Shafts that are a tight fit in holes, to prevent fretting and binding, and to aid release
  • As a lubricant between surfaces subject to high loads and slow relative movement

Dry Bearings are usually based on Molybdenum Disulphide (MoS2) or Graphite and sometimes combination of the two. Generally lubricants based on MoS2 are used in the lubrication of machines, and graphite based lubricants are used in specialised industries including hot metal working. Other specialty dry lubricants are available including Tungsten Disulphide

  • Molybdenum Disulphide is a black crystalline solid which shears easily and has a low coefficient of friction. It is resistant to solvents and chemicals and can be used at temperatures up to 250ºC.
  • Graphite has a thin flat crystalline structure that sticks strongly to metal surfaces and is a good conductor of heat and electricity. Graphite is relatively inert, being unaffected by acids, alkalis and solvents. As a lubricant it enables metal surfaces to resist seizure even at very high loads. However it results in more surface wear than MoS2. It is therefore used less for lubrication of metal surfaces than MoS2.

Dry rubbing bearings are usually plain plastic bushes that have to be able to run with marginal or no lubrication. The main requirement of dry bearings is that the bearing surfaces have a low coefficient of friction. These bearings are used in undemanding applications such as low speed moving parts in domestic appliances, instrument and electro-mechanical devices. For further information call us at +27 (0) 11 605 2434