Six inch, four jaw national chuck, with spanner

6 inch 4 jaw national chuck with spanner, made by Clark and Wellington, Queen Victoria Street, London, 1887

This lathe chuck, patented by Messrs Clark and Wellington in 1882, has four adjustable jaws, moved in and out by four radial screws. The screws are geared together by means of a ring with bevel teeth, housed within the hollow rim. The ring gears into four bevel pinions, one upon each screw spindle, so that all four screws work simultaneously when one is turned.