a head having a lock connected thereto and the lock including an eccentric rod which includes a curved outer periphery and a flat surface, a bead retractably connected to an outer periphery of the curved outer periphery, a key removably inserted into the lock and controlling the eccentric rod;

a shank having teeth defined in an outer periphery thereof and an end plate connected to an end of the shank, the end plate having a plurality of recesses defined in an outer periphery thereof and the curved outer periphery of the eccentric rod removably engaged with one of the recesses, and

a cover having a central passage through which the shank extends, the cover fixed to an underside of the head and having a chamber which communicates through a top of the cover, two detents diametrically opposite defined in an inner periphery of the chamber, the eccentric rod rotatably inserted in the chamber and the bead engaged with one of the two detents, the end plate located in a gap between the underside of the head and the cover.