Abstract: A precision drill for drilling noncircular bores, comprising a drill bit on a shaft and a holder for the workpiece being drilled, for providing a drill that can operate economically at high speeds. The workpiece holder oscillates translationally in at least one direction at a frequency controlled by the speed of the drill bit, and moves along a path determined by the desired shape of the bore to be drilled.

Abstract: Safe and structurally simple design for a finebore machine with a turning tool (3) mounted on a boring bar (2), whereby the excursion of the turning tool is produced by a piezoelectric servomotor without any magnetic actuation. This is achieved in the following manner: (a) the turning tool (3) is lodged in a spring-mounted tool holder (4) which is made to deflect by a translatory driving servomotor (6); (b) the driving direction of the servomotor (6) is perpendicular to the operating direction of the turning tool (3); (c) the driving strength of the servomotor (6) acts on the one end of a connecting rod (8) which is lodged separately from the servomotor (6); (d) the other end of the connecting rod (8) abuts on the free mobile end of the tool holder (4) in a fixed position relative to the latter. The shape of the bore to be produced can be preset as an electronic image.

Abstract: The invention relates to an attachment for the machining by stock removal of parts to be turned, particularly such which have surface longitudinal profiles which differ from the exact circular shape and may furthermore be irregular, with the aid of a tool whose in-feed movements are brought about by an electrically contolled servo-motor, whose follow-up time is very short, so that the tool nose can follow the pattern of the desired non-circular shapes without any limitation of the cutting speed which are usual in turning.