The rapid tool changing versatility and accuracy is now available to users of lathes with turret tool posts or any open slot mounting arrangement. The head is also drilled for mounting on other types of tool carriages. The newly designed models of super-precision single-dovetail heads accept any of the wide range of tool holders in the same series. This provides quick tool changing flexibility and repeat accuracy at the flick of a handle- one quarter locks holder in working position within 0.0001 inches of preset postion every time. Costly time loss due to repetetive realignment is eliminated. The socket wrench handle (included in the basic head price) is removable for possible clearance requirements when used on CNC lathes.