| 摘要 |
For drilling two holes or three holes with substantially conventional spacing between the centers of the holes using a single, adjustably positioned drill or punch, the base of the machine is provided with a rod on which at least one of the punch pedestals slides between a two hole and three hole position. Stops limit outward and inward positions of the movable pedestal so that the user need not use great care and attention in adjusting the positions of the punch. The punch comprises a sharpened tubular insert of tool steel in the end of a hollow screw which rotates in each pedestal.
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