| 摘要 |
PURPOSE:To remarkably facilitate the setting work of outside gas vent holes by boring plural outside holes at the fixed gas vent hole positions by using an outside boring machine and connecting a part of these vent holes with inside gas vent holes. CONSTITUTION:On the lifting table 30 in the outside boring mechanism, 44 pieces of drills 38 are fitted as keeping the prescribed fixed gas vent hole positions, that is, four ranks times eleven files, and guide holes 10 are arranged a guide plate 9 as the same position as the above. The cavity 4, on which the inside gas vent holes 6a-6c are formed, is shifted to the prescribed position on a plate 9, and the boring is executed on the fixed position by driving 44 pieces of drills 38. Next, the boring as shifting by the half pitch is executed and therefore, the total 88 pieces of the gas vent holes are formed and a part in them are coincided with the inside gas vent holes 6. Therefore, the setting work of the outside gas vent holes is remarkably facilitated. |
