crankshaft

A shaft carrying several cranks, usually at different angular positions, to which connecting rods are fitted in an engine, reciprocating pump, etc.

compression ratio

In an internal combustion engine, the ratio of the total volume in a cylinder at outer dead centre to the clearance volume. In powder metallurgy, the ratio of the volume of loose powder to the volume of the ‘compact’ made from it.

compressive strength

The maximum compressive stress a material will withstand, based on the original cross-sectional area.

condenser

A heat exchanger in which a vapour, e.g. steam, is condensed, usually by water flowing in tubes over which the vapour passes.

conductance

The property of a substance which makes it conduct electricity. The unit is the ‘siemens’ (symbol G). The reciprocal of resistance.

conduction of heat

Heat transferred from one part of a medium to another without motion, the heat being passed from one molecule to another.

centrifugal force

A body constrained to move in a curved path reacts with a force (centrifugal force) directed away from the centre of curvature. It is equal and opposite to the force deviating the body from a straight line called the ‘centripetal force’. Both are equal to the mass multiplied by the ‘centripetal acceleration’.

ceramics

Non-organic, non-metallic materials of brittle nature, e.g. alumina, carbides. cermet A body of ceramic particles bonded with a metal.

chain drive

A device consisting of an endless chain (usually a ‘roller chain’) connecting two wheels (sprockets) on parallel shafts.

chamfer

A corner bevelled to eliminate a sharp edge.