Abstract: A rock drill for percussion drilling comprises frontal and gauge button inserts, said frontal button inserts being parallel with the longitudinal axis of the rock drill and said gauge button inserts being inclined at an angle relative to said longitudinal axis and arranged to define the diameter of the hole drilled by the rock drill. The number of the frontal button inserts is two and the number of gauge button inserts is two.

Abstract: As a construction material in sulphurous environments at high temperatures it has according to the invention been found advantageous to use an austenitic chromium-nickel-manganese alloy having a relatively high content of manganese such as 3-12% and preferably 3-8%.

Abstract: A rotary drill bit comprising a head and a roller cutter rotatably carried thereon, wherein an annular sealing means is arranged in an annular chamber adjacent to a gap between the roller cutter and the head. At least one of the sealing surfaces of the chamber is generally seen V-shaped. According to the invention larger sealing pressure is obtained at two circumferentially spaced portions of the V-shaped sealing surface than at an intermediate portion thereof while simultaneously maintaining sealing pressure along the entire circumferential extent of the sealing means between said spaced portions.

Abstract: A milling cutter for metal cutting having a cutter body (1) in which inserts (5) are retained in recesses (3) solely by spring means (7-11). An edge (27) of the insert (5) is supported in the recess (3) on an axially displaceable adjusting device (6) which has a somewhat inclined contact surface (13). The insert (5) is adjustable without the need of loosening any clamping device.

Abstract: In material applications in which besides a high wear resistance also excellent corrosion resistance, strength and toughness are required, conventional hard metal alloys have appeared inadequate. According to the invention a hard metal alloy now exists which fulfils these requirements. It is based on WC-Ni, and the binder phase of nickel is alloyed with low, well adjusted concentrations of above all Cr and Mo.