Ladas & Parry
Method for forming hollow articles
 The method includes a step of compressing a portion of a cylindrical stock into a third section of a cavity of a die. The cavity of the die includes a first section having a polygonal internal surface, a second section being narrower than the first section and having a first circle in cross section with a diameter substantially equal to the diameter of the stock which is fed in the second section and a third section between the first and second section. The third section has a second circle in cross section with a diameter gradually decreasing from the first section towards the second section. 
San Shine Hardware Works Co., Ltd.
B
B21K
inventional
Yuan-Ho
Lee