Experimental investigations of wooden water cooled plain bearings

The use of wood as plain bearing dates back to 3500 BC. Despite of being very old technology, wooden bearings are still used in many applications like hydroelectric turbines, ships, submarines, water pumps, wheelbarrows, carts and in some food and chemical processing industries. Wooden bearing material has one main advantage over other bearing materials of protecting shafts from wear. Wooden bearings made from some woods can tolerate higher shaft speeds and loads than other materials. In Tanzania there is very little documented research done on wooden bearings though Tanzania is honored with many species of wood, both soft and hard. Thus little information is available on the properties of local hard woods as plain bearing materials. This work is an experimental investigation looking into the suitability of local wooden material as plain bearing. Ten local woods were investigated. The experimental work involved five tests; wear hardness, density, moisture content and water absorption rates. A test rig of carrying capacity 260 kg and shaft speed 750 rpm was designed for the wear test. The results of tests will assist local industries to make use of the abundant hard woods for making plain bearings. The results showed woods with low wear rates were Balbergia Melanoxylon (mpingo), Xeroderns Stuhlmannii (mnyenye) and Milletia Stuhimannii (mpangapanga). From the experimental results it is concluded that Tanzania has woods good for making plain bearings.