The steep taper mount per DIN 69871 is a suitable interface for automatic and manual tool changing. Three different forms (A, B, C) of steep taper design are covered in the standard. The most widely used form of steep taper mount is form A per DIN 69871, with trapezoidal fluting and orientation groove.
Tool steep tapers that do not have a self-locking effect must be clamped in the machine spindle through additional clamping devices. The frictional connection arising on the taper provides the torque transfer with small loads. In the case of form B, with greater loads, the key block takes the majority of the torque to be transferred. The corresponding pull studs per DIN 69872 belong to tools per DIN 69871. With the use of a predominantly hydraulically actuated collet, the tools can be very quickly and automatically changed. [WECK05], [WECK/SCHUBERT], [LEMBKE]