Back turning

The outer surfaces of the teeth, the so-called free surfaces, describe part of a logarithmic spiral in the profile

Back turning is a term used in metal processing.

It is understood to be a technique of turning , primarily for producing the tooth shape of disk-shaped milling tools ( profile milling ). The back-turning of the cutter teeth enables later sharpening without distorting the cutting edge shape of the teeth.

The tooth flank characteristic of the individual teeth of an undercut milling cutter corresponds to a section of a logarithmic spiral . In order to be able to produce this shape, the movement sequence of the lathe tool must be controlled by a cam disk or a CNC control . Back turning is therefore only possible on specially equipped lathes .

Furthermore, the cutter teeth must already have sufficiently wide slots in the appropriate places before this operation, since the lathe tool needs the gap (the later chip space of the finished cutter) to retract.

Also as background Turn is in the making "normal" turned parts inside turning designated. If, in the case of hollow parts, the inside diameter of the inside shape to be machined is larger than the inside diameter on the face of the workpiece through which the lathe tool is inserted into the cavity, the term "back turning" is also used.