| 摘要 |
PURPOSE:To prevent a gap between an inner spigot and an outer spigot and to produce cutting chips intermittently by forming recesses on the inner spigot on the inner surface of a flat plate material at both longitudinal side edges, and shaping in a cylinder and then cutting the inner spigot. CONSTITUTION:A rectangular steep flat plate material 12 is formed by pressing, and a plurality of recesses 13 which are not projected on the outer peripheral surface are formed by pressing on the inner surface 12a at both sides of the material 12. Then, the material 12 is bent roundly to shape a cylinder, and the inner spigot is then cut. At this cutting time, cutting chips are discontinued at the recesses 13, and the chips are intermittently scattered from a steel plate frame. |
