Abstract: A machining center having a magazine for storing toolholders with tools mounted therein. The magazine includes a plurality of laterally open toolholder sockets for receiving one toolholder each with its axis parallel to the tool spindle axis of the machining center. Each toolholder socket on the magazine includes a locking member enabling the toolholder to be locked in its inserted position in the magazine thereby preventing accidental withdrawal of the toolholder during rotatable movement of the magazine. Each toolholder socket on the magazine includes flange members which engage the grooves on each toolholder thereby holding each toolholder in alignment enabling the correct position of each toolholder during transfer from the magazine to the spindle of the machining center.