In a method of making a control arm, a middle piece is held in a mounting of a rotary friction welding machine so as to be constraint against rotation and movement in an axial direction. End pieces are rotated in synchronism on opposite ends of the middle piece so as to rub friction welding sites of the end pieces and friction welding sites on the middle piece on one another to initiate a friction welding process. After releasing the middle piece, the friction welding sites are compressed through axial displacement of at least one of the end pieces.