1006509-A is referenced by 6 patents.
1,006,509. Making screws. G.K.N. SCREW & FASTENERS Ltd. May 4, 1962 [May 26, 1961], No. 17122/62. Heading B3H. [Also in Divisions B4 and F2] To form a screwhead (see Division F2), by a cold heading operation on wire material, a first punch enlarges the wire end and then a heading punch 34 forms the head and its cruciform recess. A nib projecting from the headforming cavity 36 has four wings 39 for forming the grooves of the screwhead, and the side faces of the wings (when the nib is vertical) are vertical or the faces 46 are undercut as shown making an angle of 20 minutes to the vertical and the faces 47 are oppositely sloped up to 3 degrees to the vertical.; To counteract the falling away, from the punch faces, of the screwhead metal, V-sectioned ribs 40 with ridge-extensions 41 are formed on the nib between the wings 39 and these displace the screwhead metal towards the grooves formed by the wings. Instead of ridge-extensions 41, the nib may have projections of annulussegment form, describing a broken annulus, concentric with the nib axis and extending between the wings 39 beyond the ribs 40 but not contacting either.