Chuck (engineering)

ometimes referred to as "super chucks".

Special Drive System (SDS)

The SDS uses a cylindrical shank on the tool, with indents to be held by the chuck. A tool is inserted into the chuck by pressing in, and is locked in place until a separate lock release is used. SDS relies on a tool having the same shank diameter as the chuck - there are three standard sizes: SDS, SDS+ and SDS-MAX. Most used in high power hammer drills, SDS chucks are never used to hold work pieces.

Three jaw

A three jaw chuck is a rotating clamp which uses three interconnected dog (engineering) or 'jaws' to hold on a tool or work piece. Three jaw chucks are self-centring and are best suited to grip circular cross sections. Three jaw chucks can be found on lathes and indexing heads.

Four jaw

A four jaw chuck is similar to a three jaw chuck, but with four dogs, each of which can be moved independently. This makes them ideal for gripping non-circular cross sections, but difficult to centre precisely. Four jaw chucks are almost never used for tool holding. Four jaw chucks can be found on lathes and indexing heads.

Self-centring four jaw

A four jaw chuck with a mechanism for centring the work piece. Sometimes used to refer to chucks where the jaws are moved in interconnected pairs.

Magnetic

Used only for holding ferro-metallic work pieces, a Magnetic chuck consists of a accurately centred permanent magnet face.