A tubular stem (16) of a bolt mount (12) is coldexpanded into an opening (70) in a wall (72). A second wall (76) is placed against the first wall (72), with an opening (70) in it in alignment with the center opening (32) in the tubular stem (16). An elongated shank portion (88) of a tubular nut (86) is inserted through the opening (70) and then through a center opening (32) in the tubular stem (16), and into an annular space (58) defined by and between a tubular sidewall (48) of a bolt-element retainer (14) and a bolt-element (54). The tubular bolt (86) has internal threads (90) that mesh with and thread onto external threads (56) on the bolt-element (54). The tubular nut (86) is rotated until a head (84) on its end is in tight clamping engagement with the portion of the second wall (76) that surrounds the opening in the second wall. Tightening of the tubular nut (86) draws the bolt-element retainer (14) and the tubular nut (86) together, firmly connecting the second wall (76) to the first wall (72).