摘要 |
A method and mechanism for forming a hole through a forged workpiece. During the forging operation an indentation is formed in the upper surface of the workpiece. While the workpiece remains in the forging press, a trepanning tool is placed in the indentation and the top die of the press is used to force the tool almost through the workpiece leaving a thin wall at the bottom of the hole. The workpiece either may be removed from the press while the wall is knocked out to complete the hole, or preferably the workpiece remains in the press and the top die is used to knock out the wall. If the workpiece remains in the press, preferably it is supported on a locating ring which aligns the workpiece and trepanning tool with the top die. Also disclosed is an improved trepanning tool which has external and internal sloping faces extending around its circumference at its lower end.
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