Abstract: A polygonal turning machine with a rotating knife head, and a workpiece carrier rotating synchronously to the knife head, the carrier being arranged on a support, characterized in that, the axis of the workpiece carrier is able to be brought into a coaxial position to the axis of rotation of the knife head.

Abstract: A knife head, particularly for multi-edge lathes having knives held in plates and braceable in their operating position, which plates are adjustable, in order to obtain a radial adjustability of the knives, by means of an eccentric tool which is insertable in a bore in the knife head. There is coordinated to the eccentric tool-insertion bore which is directed onto the rear surface of the plate, a recess laterally offset thereto which is formed in the rear wall of the plate for the insertion therein of an eccentrically offset end of the eccentric tool.