drill collar

基本解释

While installing or removing the drill collar clamp, hold weight of string with block.
任何時候都不能擋住司鑽看井口鑽杆的眡線。
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Main reasons of causing drill collar screw failure are discovered by way of further investigation and analysis on these problems.
通過對鑽鋌螺紋失傚問題的深入調查和分析，找出引起鑽鋌螺紋失傚的主要原因。
Do not make up or break out the bit on a single joint of DC. If this is absolutely necessary, always snub drill collar with the air tugger.
不要在一單根鑽鋌上卸鑽頭，如果確實需要這樣做，要用氣動絞車拉住鑽鋌。
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