摘要 |
A reversible casing (9) for a down-the-hole drill has a predetermined snap ring (50) groove length centered between the casing ends (11, 15), based upon the casing bore (42), the snap ring groove depth and the snap ring body length, whereby a snap ring (50) will be retained in the snap ring groove (72), while permitting lengthwise movement of the snap ring (50) during reverse orientation of the casing (19).
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