Abstract: A reamer and stabilizer assembly for rock drills having a substantially cylindrical body provided with a threaded end socket for connection to a drill stem, the body having circumferentially spaced longitudinally extending recesses for receiving reaming and stabilizer rollers mounted on axles extending parallel to the axis of the body, each reamer and roller assembly being removably retained in its recess by a keeper pin which can be inserted or retracted through a keeper pin passage opening into the threaded socket and into a longitudinal passage through each axle.