Abstract: An arrangement in hand-held grinding machines intended for grinding the buttons of button drill-bits and provided with a driven spindle which carries a grinding disk. The grinding disk presents a profiled groove for shaping respective buttons of the bit to their intended tip profile. In order to enable buttons to be ground quickly and effectively with the aid of a hand-held grinding machine without needing to rotate the button to be ground about its own longitudinal axis, there is provided a spring-steel guide-spring which is mounted fixedly in relation to the grinding disk and which presents on both sides of the disk (4) obliquely and inwardly extending fingers which are intended to engage the button to be ground when the grinding disk is brought into engagement with the button.

Abstract: An abrasive wheel for grinding the cutting pins of a button-type drilling bit in a grinding machine of the kind provided with a rotatable holder for fixating the pins of the bit in a grinding position and for rotating thus fixated pins. The machine also includes a spindle on which the abrasive wheel can be mounted in a given position. The spindle/holder is linearly movable in a plane which extends through and is contained by the respective rotational axes of the holder and the spindle and in a direction parallel with the rotational axis of the spindle. The abrasive wheel includes circular flange parts which embrace a profiled groove therebetween. To enable cutting pins to be ground to an obtuse tip-profiled shape with the aid of such an abrasive wheel, the profiled groove, when seen in cross-section, is formed symmetrically around a line which intersects the rotational axis of the abrasive wheel at an angle whose complementary angle is equal to the angle of inclination of the spindle.