N the adjustable metal spike attached to the bottom of a cello, double bass, etc, that supports it while it is being played 弦轴 [music]
Hundreds of end-pin and end-plug options are available in a variety of material types.
还有数百种钉子和软塞类型以不同材料制造供选择。
Tighten the elastic a little. Pin the free end to the facing.
把松紧带收紧一点用大头针把没固定的一端钉在贴边上。
Its upper end is drill pipe box or union, the nether end is casing pin. It is a crossover with hollow inside.
它是个上端为钻杆母扣或者由壬，下端为套管公扣，内空心的转换接头。
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