Method for the fabrication of a screw member for plate member fastener

Abstract

A method for making a screw member for plate member fastener is disclosed to include the step of preparing a metal element subject to a predetermined size and then processing the metal element through a cold extrusion forging operation to form a head at one end, a connection portion at an opposite end and a shank between the head and the connection portion, the step of processing the connection portion through a thread rolling operation to form threads around the periphery, the step of processing the threads to form a stop end edge at one side in proximity to the shank, and the step of finishing the final product.

1 . A method for making a screw member for plate member fastener, the method comprising the steps of:
 (a) Prepare a metal element subject to a predetermined size, and then process said metal element through a cold extrusion forging operation to form a head at one end, a connection portion at an opposite end and a shank between said head and said connection portion.   (b) Process said connection portion through a thread rolling operation to form threads around the periphery of said connection portion   (c) Process said threads to form a stop end edge at one side in proximity to said shank.   (d) Finish the final product.   
     
     
         2 . The method of  claim 1 , wherein the step (a) is to put the prepared metal element put in between an upper die and a bottom die of a forging machine for enabling the metal element to be forged to form the desired shank and the desired connection portion, and then to attach a hammer forging die to one end of the metal element outside the upper die and the bottom die and to hammer the hammer forging die in forging the respective end of the metal element into the desired head. 
     
     
         3 . The method of  claim 1 , wherein the step (b) is to put the shape-formed metal element thus obtained from the step (a) in between a thread rolling face of a first flat thread rolling die of a first thread rolling die set of a thread rolling machine and a thread rolling face of a second flat thread rolling die of said first thread rolling die set of said thread rolling machine, and then to reciprocate the first flat thread rolling die and second flat thread rolling die of said first thread rolling die set in reversed directions so as to form the desired threads around the periphery of the connection portion. 
     
     
         4 . The method of  claim 3 , wherein the step (c) is to put the semi-finished screw member thus obtained from the step (b) in between a first flat thread rolling die of a second thread rolling die set of said thread rolling machine that has a thread rolling face at one side thereof and an end edge-forming face suspending in the thread rolling face and a second flat thread rolling die of said second thread rolling die set that has a thread rolling face at one side thereof, and then to reciprocate the first flat thread rolling die and second flat thread rolling die of said second thread rolling die set in reversed directions in forcing the respective thread rolling faces against the connection portion of the semi-finished screw member and causing said flat end edge-forming face to cut an end portion of one last thread of the threads of the semi-finished screw member into the desired stop end edge.