Patent ID: 8388796

Claim:
A method for bonding a metal member comprising: forming a metal insertion coupling having a socket portion; forming the socket portion with an insertion hole in which an end portion of a metal member is inserted and bonded with adhesive, wherein the tensile strength of the socket portion at its deepest portion in the direction of the center line of the insertion hole is equal to or higher than the tensile strength of the metal member in the direction of the center line; forming an outer surface of the socket portion with a tapered surface increasing gradually from an opening end to a back side; forming the insertion hole to have a width in the range of 0.2 mm-0.6 mm larger than the end portion of the metal member; quenching or cold working the end portion of the metal member; pressing the end portion of the metal member into the insertion hole; and densely providing an adhesive between the end portion of the metal member and an inner surface of the insertion hole.