TAPERED SCREW ROLLING METHOD FOR PIPE MATERIAL

PURPOSE: To execute a process by one process, and to shorten the working time by constituting a rolling roller of a rolling forming screw part having a desired tapered gradient and a desired lead angle, and a drawing forming screw part having a tapered peripheral surface part whose gradient is larger than a tapered gradient, which is adjacent to said part. CONSTITUTION: A pipe 30 is allowed to contact a rolling roller 10 through a holding member 27 and fixed coaxially to an axis Y by a clamp handle 29. The pipe 30 is engaged on the peripheral surface of a drawing forming screw part 3, and as a head 9 rotates, a shaft 11 which has been installed to the head 9 rotates centering around an axis Y, the shaft 11 body also rotates centering around an axis Y together with the roller 10, and a screw 33 is carved and provided one after another from the end part of the pipe 30. Also, as the screw 33 is carved and provided, a head 9, a motor 13, and a motor supporting base move automatically in the ...