Probe head

A manually operable probe head (10) has a support (12), by which the probe head may be attached to the head of a coordinate measuring machine, a first rotor (14) rotatable about an axis (16) relative to the support (12), and a second rotor (46) rotatable relative to the first rotor about a perpendicular axis (47). The first rotor (14) and second rotor (46) are each rotatable through a plurality of kinematic rest positions, into which they may be axially urged through retraction of a tie bar (90). Location of the first and second rotors when not in their rest positions is achieved by three spring loaded pistons (34) and (72). The pistons (34) and (72) ensure that even when not in their rest positions, the first and second rotors always come to rest adjacent such a position. The second rotor (46) carries a connector (54) for receiving a touch probe (50). The connector (54) is recessed within the probe head in a bore (52), behind the axis (47), and this provides a smaller reduction in the operating envelope of the machine (caused by the use of the probe head (10) in connecting the probe to the machine).