Abstract: A drill is described having a metal bit carrier part on which a sintered metal bit is placed. The bit possesses at least one enclosed helical cooling channel which continues in alignment into a corresponding cooling channel in the bit carrier part. This drill is particularly characterized by very great mechanical and thermal stability, which is not adversely affected in any way by the system of cooling channels in the interior of the drill, so that the service life and cutting power of the drill can be greatly increased. These advantages apply both to twist drills proper and to single-lipped deep-hole drills, for which there is the particular advantage that the geometry of the drill head can be optimally adapted to the particular material to be processed.

Abstract: Described herein is an apparatus for grinding a twist drill bit, especially for web thinning and split pointing of the tip of a twist drill. The apparatus includes a grinding disk and a drill bit holder movable relative thereto mounted on a support. The support may execute relative motion with respect to the grinding disk under cam control in two coordinates and using a grinding disk having an invariable profile, in order to produce tip grinding patterns of various types. Preferably, the cam control is performed by means of interchangeable templates so that it is possible, using only a single grinding disk, no longer subject to the necessity of dressing, to produce a multiplicity of tip surface patterns that are optimally adapted to the given drill bit geometry.