| 摘要 |
<p>1,223,211. Rolling threads. REED ROLLED THREAD DIE CO. 31 March, 1969 [1 April, 1968], No. 16745/69. Heading B3M. A thread-rolling die, which is used with a similar die to roll a gimlet-pointed screw from a headed cylindrical blank, includes a flat surface A for threading the body of the screw, and a flat inclined surface C for threading the point, the surface A being of increased width J at its leading end to help in stabilizing the blank. In order to provide the increased width, a surface E, which produces a slug on the end of the screw, is formed so that it extends only over a length M without reaching the end 18 of the die. Both the surface A and the surface E can be provided with transverse notches X<SP>1</SP> to help in gripping a blank.</p> |
