Abstract: A shank (4) of the chuck (1) has an axially located cylindrical opening (41) for holding a fixation lug (5) of a tool (6). A stop piece (11, 12, 13) provided with a rack-like tooth member (14) is axially movably mounted in a bore (10) which is also axially located. An adjustment shaft is inserted in a bore (15) located at a right angle to the chuck axis and provided with a second toothed member (17) which engages with the first toothed member (14) on the stop piece. This makes it possible to adjust the stop piece (11), one end (12) of which forms the stop for the fixation lug (5) of the tool (6), from the side of the chuck. The time-consuming repeated removal and insertion of the chuck from a presetting device, as occurs in prior art devices, can be eliminated.

Abstract: A tool support, or an extension or reduction part holding a tool support, is held by its shank in an axial bore of a socket of the tool-holding device. The socket has one or more further bores, the longitudinal axes of which each form an angle of from 0.degree. to about 5.degree. with a straight line perpendicular to the longitudinal axis of the socket. A setscrew disposed in one such further bore cooperates by means of a beveled or faceted surface at its lower end with a chucking surface running on the outside of the shank at an angle to the longitudinal axis thereof. Another setscrew may cooperate with a second such chucking surface forming an angle of about 45.degree. with the first chucking surface.