Camshaft pulley wheel, 1994-1995.
© Science Museum / Science & Society Picture Library
The camshaft pulley needs to be very accurately made and strong as it is used in a motor car. Metal powder is dropped into a die and a punch preses the powder into shape with a force of 250 tonnes. The shape is then ejected. At this stage it is quite weak as it is just presed powder, so the metal must be heated, or sintered, and carefully cooled to give a solid, strong pulley. Made by GKN Bound Book.