Dividing head or indexing head is a special work holding device, which is bolted on the machine table. The work may be mounted on a chuck fitted on the dividing head spindle or may e supported between a live and dead center. The dead center is mounted on a foot stock as in a lathe tail stock that is bolted on the machine table after correctly aligning its spindle axis with the dividing head spindle. The attachment is principally used for dividing the periphery f a work piece in equal number of divisions for machining equally spaced slots, or grooves. The worm and worm gear driving mechanism of the attachment can be linked with the table lead screw for cutting equally spaced helical grooves on the periphery of a cylindrical work piece.