摘要 |
An improved forming roll for forming cylindrical metal slugs from cylindrical rod stock is characterized in that the roll has a helical groove defined by a rib the radial height of which and the axial dimension of which increase along the length of the roll, the groove between successive helices of the rib having a cylindrical base the axial length of which is so dimensioned that the volume of metal enclosed by the groove, in use, is substantially constant. |