Abstract: Machine for machining a groove round the external periphery of the base of a nozzle and notably enabling the back of a weld to be reworked from the outside when a nozzle is being installed on a nuclear reactor vessel.The machine comprises a cylindrical drum (5) in two parts (41, 45) equipped with locking and position-holding shoes (6), a machining head driven in rotation by means of a gear ring (9) and a pinion (17). The cylindrical drum (5, 41, 45) is locked and held in position with respect to the nozzle (1) by means of an intermediate coupling ring (23) secured by screws (31) to the nozzle (1) and by the locking shoes (6) fixed to hydraulic rams (47).

Abstract: Device having movable jaws for gripping the shank of a pin or bolt is provided with ridges or grooves on the jaws which mate with corresponding ridges or grooves on the shank. The jaws are mounted to slide toward and away from each other and this sliding movement is induced by linkage pivotally connected to the jaws. An abutment is provided for limiting the movement of one of the jaws so that actuation of the linkage causes movement of said one jaw until it strikes the abutment followed by movement of the other jaw.