Assembly and Disassembly: Bearings

About this unit

Bearings support rotating shafts and allow them to turn with little friction and wear. In this unit you study two simple sliding (journal) bearings, the open bearing and the bush bearing. You learn to draw them as assembly drawings (all parts fitted together) and as disassembly or detail drawings (each part shown separately). This builds the important skill of reading how parts fit and work together.

Key ideas

• A journal is the part of a shaft that turns inside a bearing.
• Bearings usually have a cast iron body and a replaceable liner or bush of softer metal such as gunmetal or brass.
• The bush is prevented from rotating and from moving axially by features such as collars, snugs or set screws.
• Assembly drawings show parts in working position; disassembly drawings show each part separately with its own views.
• Sectioning conventions: shafts, bolts, screws and pins are not hatched when cut along their axis; adjacent parts are hatched in opposite directions.

How to prepare

Learn the name and function of every part of each bearing, and practise converting a set of part drawings into an assembled sectional front view, and the reverse. Pay attention to which parts are hatched, to the oil hole, and to how the bush is held in place.