Manufacturing method for a press work product

Abstract

To provide the manufacturing method for the press work product reducing the chance of causing distortion of the countersink as press-forming the countersink. This is the manufacturing method for a press work product which has a tapped bore for a stem of a flat countersink head screw to penetrate therethrough and a countersink formed around a circumferential line of the tapped bore for a head of the flat countersink head screw to seat therein, comprising steps of forming a work as the press work product by punching a plate material, trimming an outside diameter of said work, and forming said countersink by inserting said work after trimming the outside diameter into a press die to press form thereof.

1 . A manufacturing method for a press work product which has a tapped bore for a stem of a flat countersink head screw to penetrate therethrough and a countersink formed around a circumferential line of the tapped bore for a head of the flat countersink head screw to seat therein, comprising the steps of: 
 forming a work, to be the press work product, by punching a plate material;    trimming an outside diameter of said work; and    forming said countersink by inserting said work, after trimming the outside diameter, into a press die to press form thereof.    
   
   
       2 . The manufacturing method for the press work product according to  claim 1 , wherein: 
 said press work product is in a disc-shape and    said tapped bore and countersink are formed on plural positions around a stem center at outer side of the press work product.    
   
   
       3 . The manufacturing method for the press work product according to  claim 1 , wherein 
 depth of said countersink is equal or greater to 0.5 times the thickness of said work.    
   
   
       4 . The manufacturing method for the press work product according to  claim 2 , wherein 
 depth of said countersink is equal or greater to 0.5 times the thickness of said work.