Abstract: A machine reamer has a base and a reamer head configured as a one-piece indexable insert that axially projects beyond the front of the base. The indexable insert can be introduced in a front insert seat of the base with an axially projecting, preferably conical shoulder and can be clamped therein by a tension rod that extends through the center-axis of the base. In order to improve the rotational catch effect between the base and the indexable insert, the indexable insert has a central polygonal opening through which the tension rod engages with a complementary polygonal section.

Abstract: A reaming tool is capable of reaming out several axially interspaced borings of a workpiece. The reaming tool includes a guide shank that can be clamped into a machine spindle and which can be supported in prepared borings of the workpiece to be machined by using external supporting elements. The reaming tool also includes a reaming head coaxially connected on the front end thereof. In order to be able to easily change a worn tool, the reaming head is connected to the guide shank by an auto-centering clamping mechanism. The supporting elements positioned in the proximity of the clamping mechanism can, during a clamping process, be radially spread outwardly from a smaller dimension to a predetermined diameter guide dimension.

Abstract: For correcting axial errors of a tool, the latter is held by a two-part tool holder, whose two parts are reciprocally displaceable by a setscrew along their engaging interfaces at right angles to the axis. For this purpose, the locking screws of a flange connection are correspondingly loosened. The axial correction can be simply and rapidly performed, in that the setscrew is provided on a setting ring rotatable about the axis.

Abstract: A coolant and lubricant is supplied to the cutter head through the shank of a reamer. For this purpose an axial channel extends through the reamer shank and encloses in its front part a conical screw used for adjusting the cutter head and whose threaded shank has at least one longitudinal slot, so that the coolant and lubricant passes through the threaded shank into a ring channel in the front region of the reamer. The coolant and lubricant flows from said ring channel via outlet channels between the cutters. The outlet channels slope outwards in the direction of the leading edge of the cutters, so that an optimum cooling and lubrication of the latter is obtained.

Abstract: In the known, adjustable, single-cutting-edge machine reamers having a turnable cutting plate, the adjusting and re-adjusting operations are awkward and associated with difficulties because, at least as far as adjusting is concerned, adjustments have to be made at two points, and moreover for adjusting to the set desired value it is generally necessary to proceed in a step-by-step manner, gradually working ones way up to the desired value. These problems are due to the fact that adjustment can in principle only be made in the forward direction, that is to say in the direction of increasing diameter, whereas reverse adjustment in the proper meaning of the term is not possible but can only be achieved indirectly by carrying out a new adjustment with a lower starting value and adjusting in a forward direction.