Screw mfg. using continuous rod threading - is followed by parting and welding to head to accelerate prodn.

摘要

Fast and economic manufacture of screws is achieved by the separate production of the threaded shank and the head which are then joined together by welding. The shank can be threaded either by cutting tools or by rolling while the head can be formed by blanking. The separation of the two processes permits various types of heads to be made by simple means and in smaller series. Pressing of the head (40) allows a recess (44) to be formed for the small end (43) of the screw shank (41) so that a corrugated locking washer can be interposed between the head and the shank. The head may also be pressed with deflections actins as biting serrations when the screw is threaded home.