Method of making steel couplers for joining concrete reinforcing bars

A method of making a tubular rebar coupler for rigidly connecting opposing end portions of first and second concrete reinforcing bars, comprising the steps of inserting a solid steel rod section into a first cavity of a first die member with an inner end surface of the rod section opposing an end surface of the die cavity, forcing a first punch along an axis into a solid first end portion of the rod section to form a first bore and a tubular first end portion of a coupler body, removing the coupler body from the cavity of the first die member, heat treating the coupler body, inserting the coupler body into a second cavity of a second die member having a second punch projecting into the second cavity, forcing one of the punches into the first bore to lengthen the first bore and first end portion and to form a second bore and a tubular second end portion for the coupler body, the first bore adapted to receive the end portion of the first concrete reinforcing bar and the tubular first end portion of the coupler body adapted to be compressed radially inwardly against the end portion of the first concrete reinforcing bar, and forming the tubular second end portion of the coupler body for connecting to the end portion of the second concrete reinforcing bar.

A method of making a tubular rebar coupler for rigidly connecting opposing end portions of first and second concrete reinforcing bars, comprising the steps of inserting a solid steel rod section into a cavity of a first die member with the cavity having an inner extension smaller than the rod section, forcing a punch along an axis into a solid first end portion of the rod section to form a bore and a tubular first end portion of a coupler body and to force the rod section at least partially into the inner extension of the cavity, removing the coupler body from the cavity, heat treating the coupler body, inserting the coupler body back into the cavity, forcing a punch into the coupler body through the bore to lengthen the bore and the first end portion of the coupler body and to fill the extension of the cavity to form a solid reduced second end portion of the coupler body, the end portion of the first concrete reinforcing bar adapted to be inserted into the bore and the tubular first end portion of the coupler body adapted to be compressed radially inwardly against the end portion of the first concrete reinforcing bar, and forming external threads on the second end portion of the coupler body for connecting to the end portion of the second concrete reinforcing bar.