| 摘要 |
<p>A method for the manufacture of nails of the type which have along at least the major portion of the nail shank tapered protrusions of which the narrow ends are directed towards the nail tip, and which are preferably disposed helically around the nail shank comprises the steps of rolling an elongated blank in a first rolling step to impart to it a cross-sectional shape comprising a plurality of circumferentially spaced lobes, depressing these lobes in a second rolling step while simultaneously forming the tapered protrusions and reducing the cross-sectional area of the blank by using rolls (20, 21) whose operative surfaces have die matrix cavities corresponding to the tapered protrusions, and cutting the rolled blank into nails which are provided with a head. <IMAGE></p> |
