Bearings

Q What is OILITE Bronze?

A A self lubricating (oil-impregnated) bearing material made from powders of copper.

Q Where can I get help on the correct choice of copper alloy bearing material?

A Consult CDA publication Pub 45 Copper Alloy Bearings .

Q What is a water lubricated bearing?

A In the marine industry, rubber lined bearings, generally called 'cutlass bearings', have a long history of successful application. Water lubrication is cheaper and environmentally cleaner than say oil or grease lubricated stern gear for example.

The fundamental principle of water lubricated bearings is based upon the ability to form a film of water between the shaft and bearing surface. The film of water is of sufficient volume to separate both surfaces. The materials used for the shell (which are usually made from tube) include naval brass, aluminium bronze, gunmetal and tin bronze.

Q I am looking for a copper alloy bearing material to operate between a stainless steel shaft and a stainless steel plate both of hardness about 700HV. I require the bearing to have a hardness of about 400HV.

A The only copper alloys to meet the hardness requirement are the CuBe alloys. The alloy CuBe2 (CW101C) UNS C17200 when aged at 315oC will have the required hardness.

Further details of the other properties required in bearing materials may be found in CDA publication Pub 45 Copper Alloy Bearings .

Q I am designing a hinge in a lock gate which is underwater and since access is difficult I am looking for a maintenance free bearing for a hinge. What do you suggest?

A cast tin bronze bearing which will have the required corrosion resistance. These are available with carefully machined holes which are filled with a solid lubricant consisting of graphite plus oil. During service a thin film of lubricant is produced as the bearing slowly wears.