| 摘要 |
PROBLEM TO BE SOLVED: To prevent a fluctuation in a product dimension, and reduce a cost by forming at least one of a cylindrical member, forming a projecting part on the inside surface or an outside surface of the other member, and setting hardness of a projecting part forming member larger than hardness of the other member. SOLUTION: A projecting part 16 is formed into a circumferential shape in an inside surface intermediate part of a small diameter part 15 of a cylindrical eraser receiver 3, an inside diameter X of a part other than that is formed in the almost same diameter as an outside diameter Y of an extrusively molded core tank 2, and the eraser receiver 3 is formed of a construction material having hardness higher than the core tank 2. An inside diameter Z of the projecting part 16 is set smaller than the outside diameter Y of the core tank 2, and the projecting part 16 bites in an external shape of the core tank by this difference and a hardness difference of the construction material. The eraser receiver 3 arid the core tank 2 are stably connected by this biting-in and installation with the mutual same diameter parts other than that. Polycarbonate and unsaturated polyester are cited as a construction material of the eraser receiver 3, and a vinyl chloride resin and a methacrylic resin are cited as a construction material of the core tank 2. With such constitution, a metal mold can be easily and inexpensively manufactured. |
