| 摘要 |
PURPOSE:To simply and effectively prevent a plating from peeling by forming masking recessed portions on the circumferences of respective port openings of a cylindrical material, plating the respective portions while masking means are provided in side wall regions and cutting the outer diameter of the cylindrical material. CONSTITUTION:In manufacturing a sleeve 10, masking recessed portions 21 deeper than a predetermined finishing outer diameter part D are formed on the circumferences of respective port openings 12A, 13A on an outer face of a cylindrical material 14 prior to plating. Then, masking material 22 such as paint is applied on the side wall areas of the masking recessed portions 21. Next, the inner diameter part of the cylindrical material 14, the respective port openings 12A, 13A and the bottom areas of the masking recessed portions 21 are plated 15. The inner diameter part of the cylindrical material 14 on which the plating 15 is applied is honed. After that, the outer diameter part D of the cylindrical material 14 is cut into a finish dimension D to complete the sleeve 10. |
