for cutting grooves in an internal circumferential portion of a sintered material 15 fig8 a 9b show die for use in final forming referring to fig8 reference numeral 23 denotes a upper punch numeral 33 denotes a lower punch and numeral 42 denotes a core on an internal circumferential side of a lower end face of the upper punch 23 is formed a protruding edge 23a which is protruded downward along an entire circle of the circumferential portion likewise on an internal circumferential side of the lower punch 33 is formed protruding edge representation is omitted which is protruded upward along an entire circle of the circumferential portion a diameter of the core 42 is smaller than a most inside diameter of the sintered material in which grooves are made next a method for producing the bearing using the above die will be described first the sintered material 15 is placed in die shown in fig7 b and compressed by the lower and upper punches 22 32 consequently plastic flow occurs in the entire sintered material 15 so that its internal circumferential portion is contracted thereby being in firm contact with an external circumferential portion of the core 41 as a result portions corresponding to the protruded portions 41a of the core 41 of the internal circumferential portion of the sintered material 15 are made to the grooves 15a shown in only fig9 a 9b next the sintered material 15 is taken.