Abstract: A device in a drill string component for percussive rock drilling including a thread for threading together with another drill string component including a complementary thread. The thread includes a thread groove formed by two thread flanks and an intermediate thread bottom. In operation one of the flanks forms a pressure flank. The thread groove has an essentially equally shaped sectional form along its axial extension. The thread bottom exhibits at least three surface portions with part-circular shape, as seen in an axial section. The surface portions with part-circular shape have increasing radiuses, as seen from each thread flank to an intermediate surface portion of the thread bottom. Also a thread joint and a drill string component.

Abstract: A device in a drill string component for percussive rock drilling including a thread for threading together with another drill string component including a complementary thread. The thread includes a thread groove formed by two thread flanks and an intermediate thread bottom. In operation one of the flanks forms a pressure flank. The thread groove has an essentially equally shaped sectional form along its axial extension. The thread bottom exhibits at least three surface portions with part-circular shape, as seen in an axial section. The surface portions with part-circular shape have increasing radiuses, as seen from each thread flank to an intermediate surface portion of the thread bottom. Also a thread joint and a drill string component.

Abstract: A connection rod (1) for rock drilling includes a first rod part (2) whidh has an external thread (4) provided at one end thereof, wherein the end of the rod opposite to the one end includes an end portion (6) which carries an internal thread (5), wherein the end portion (6) is joind to the first rod part (2) by friction welding and wherein the end portion (6) has been heat treated prior to being joined to the first rod part (2). The invention also relates to a method of producing such a connection rod.

Abstract: The present invention relates to a connection rod (1) for rock drilling comprising a first rod part (2) which has an external thread (4) provided at one end thereof, wherein the end of the rod opposite to said one end includes an end portion (6) which carries an internal thread (5), wherein the end portion (6) is joined to the first rod part (2) by friction welding and wherein the end portion (6) has been heat treated prior to being joined to said first rod part (2).

Abstract: A thread coupling for percussive drilling has a first drill string element (2) with an internal thread (3) and a second drill string element (6) with a spigot (7) which is provided with an external thread (8) for cooperation with the internal thread (3). A contact surface (10) on the second drill string element (6) is lined with a wear resistant additional material which covers 50-100%, preferably, 50-90%, of the contact surface. The wear resistant material is preferably a stellite which has been applied by means of plasma welding, or is a ring which has been soldered to the contact surface.