1,216,566. Tool changing WERKZEUG-MASCHINENFABRIK OERLIKON BUHRLE A.G. 5 Sept., 1968 [5 Sept., 1967], No. 43379/68. Headings B3B and B3T. A machine tool such as a lathe comprises automatic tool changing means in the form of a drum magazine 21 on which are stored tools 20, 20a, 20b, ... in respective tool holders 12, 12a, 12b &c., the drum being mounted on a carriage 3, movable along the lathe bed 1, and rotatable about a horizontal axis at right angles to the bed, a cross slide 4 mounted on the carriage 3 has a tool holder mounting 11 in which a selected tool holder is clamped during a machining operation on a workpiece WS. A tool transfer mechanism supported on the carriage 3 is provided between the magazine 21 and the tool slide 4 and is constituted by a conveyer channel 31 in which a gripper carriage 33 travels to move a selected tool holder along a linear path towards or away from the magazine. In a tool changing operation the gripper carriage 33 moves from a start position S to a reverse position U where it engages a tool holder 12b which is released from the magazine and then moves back along the channel 3 with the tool holder to a position " O " where it remains at rest until the cross slide 4 carrying a " used " tool holder 12a is fully retracted along a linear path 5a. The used tool holder 12a is released by the mounting 11, and the gripper carriage with the new holder 12a is moved into the change position W which displaces the old holder from the slide path 5a. The new holder is then engaged by the mounting 11 on the cross-slide and released from the gripper carriage whereafter the crossslide is moved with the new tool holder 12b into its operative position along the path 5a. The empty gripper carriage 31 then continues to move towards the old tool holder which it engages and subsequently displaces it to the magazine on which it is clamped, the carriage then moving back to the position " S " to await the next tool changing operation. The clamping of the tool holders in the magazine, gripping carriage and tool mounting 11 is effected by fluid pressure means and the whole sequence of operation is effected by electro fluid means controlled from a punched tape.