| 摘要 |
<p>A nut (20) having a plurality of thread convolutions (36, 38, 40) is formed with a plurality of punches from a metal blank to eliminate time consuming tapping operations. To make the nut (20), a pair of punches are used to form recesses in opposite sides of the blank and to form projections which extend axially outwardly from the sides of the blank. The recesses are separated by a web which is shaped by another pair of punches to form an inner thread convolution (36). The two axially extending projections each contain a volume metal which is the same as the volume of metal contained in upper and lower thread convolutions (38,40). The upper and lower thread convolutions (38,40) are formed by cold working the metal of the blank to eliminate the axial projections and form radially inwardly extending projections in the central opening in the blank.</p> |
