Abstract: An adjustable taper ring collar for use in manufacturing rings comprises a generally cylindrical member having a plurality of longitudinal slits therein, the sections of the cylindrical member between the longitudinal slits being expandable in the radial direction of the collar to retain a ring or the like thereon. An adjustment mechanism is provided on the collar and which is movable in the longitudinal direction of the collar for abutting against a side surface of a ring or the like at a plurality of spaced apart locations around the circumference of the ring in order to firmly support a ring around its entire circumference during machining of the ring.