A THREAD JOINT, A MALE PORTION AND A FEMALE PORTION
The present invention relates to a male portion a thread joint and a male portion for percussive drilling. The threaded joint includes at least one generally cylindrical external thread (14) and one generally cylindrical internal thread (15). The external thread (14) is provided on a spigot intended to constitute an integral part of a first drill string component (10A, 10B). The threads comprise thread ends provided in connection with associated full profile threads. The threads (14, 15) comprise end areas where each thread in a longitudinal section has its smallest radius. Conical guiding surfaces (25-28) are provided axially at each side of the threads (14, 15). The outer and inner ends of the spigot include conical guiding surfaces (25, 26) for cooperation with the conical guiding surfaces (27, 28) axially on each side of the internal thread (15). The imaginary cone apices of the conical guiding surfaces (25-28) are directed in an impact direction (F) and form an angle ( alpha ) with the centerline (CL) of the thread joint (10), said angle ( alpha ) being in the interval of 1-20 DEG .