它基本上由在淬硬钢衬套下将零件夹持到位的夹持装置组成，钻孔作业中钻头穿过这些衬套，通过它们来导向。

Basically it consists of a clamping device to hold the part in position under hardened-steel bushings through which the drill passes during the drilling operation. The drill is guided by the bushings.

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舵栓采用铸造钢并用不锈钢套和一个合成衬套轴承安装。

Rudder pintle to be forged steel and fitted with stainless steel sleeve and a synthetic bush bearing.

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本文介绍了地下储油库渗漏水的防治方法，并选用了玻璃钢及聚氯乙烯塑料薄膜制作罐室防水防潮衬套。

Here is a way to prevent underground oil storage tank from permeation of water, in which glass steel and polyvinyl chloride film are used to serve as damp-proof lining.

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