A machining tool, especially a milling tool, includes a shaft-like holder
defining a longitudinal axis (13). A seat (9) is provided in the front
face of the holder for a cutting plate that can be inserted into the
holder. The cutting plate has a coupling part for mounting in the seat
(9) of the holder. The coupling part has three ribs which project axially
from the end surface of the cutting plate that is opposite the holder and
which extend radially. The ribs are provided for engagement in
complementary grooves (31) configured in the seat (9) of the holder.
Their side walls (37 and 35) form driving surfaces and support surfaces,
which interact for transmitting a machining torque, or as axial position
safety-catch, with corresponding surfaces of the flanks of the ribs of
the cutting plate. The driving surfaces and the supporting surfaces are
formed by limited partial surfaces (43 and 41) of the side walls (37 and
35) of the grooves (31) whose other surfaces are retracted in relation to
the partial surfaces (43 and 41) to form a spacing between the ribs and
the walls of the grooves (31).