| 摘要 |
A method of manufacturing a ram configured to be mounted for reciprocation in a guide tube section of a powered hammer. The ram includes an outer circumferential surface, a radially outwardly projecting sealing portion, and a helically shaped vent channel defined in the circumferential surface and running from a front end portion of the circumferential surface to a rear end portion of the circumferential surface and being interrupted by the sealing portion. The method includes forming the outer circumferential surface of the ram and the helically shaped vent channel in a single manufacturing operation. For example, the method includes rotating a blank on a machine tool, forming the outer circumferential surface of the ram by applying a first machine tool bit to the blank while the blank is rotating, and forming the helically shaped vent channel in the outer circumferential surface by applying a second machine tool bit to the blank while the blank is rotating, without removing the blank from the machine tool.
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