Tool head mounting arrangement for a lathe

A tool heading mounting arrangement in a turning machine of the type having a carrier and tool head clamped against seating surfaces therein, said tool head being adjustable in position relative to the workpiece, said carrier containing an opening for receiving said tool head, said opening including an upper seating surface and a lower seating surface against which said tool head rests, a rotatable clamping means provided in the carrier for retaining said tool head in place, said clamping means comprising a body having a transversely running threaded bore for receiving a clamping screw for clamping the tool head, said body being mounted rotatably in the carrier, said carrier being provided with a recess dimensioned so that the clamping screw can be moved selectively into upper and lower positions in which it is displaced from the guide opening in the carrier to permit insertion and removal of a tool head.