Spindle feeds and speeds are controlled by selector levers which engage the proper gears in the drill head.

主轴的进能量和转速是通过选速杆使主轴箱中的适当齿轮相啮合而控制的。

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This paper introduces the 'structure characteristics and rock fragment characteristics of single step drill head with point pick.

介绍了单阶梯尖环齿钻头的结构特点及碎岩特点。

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The drill head for manually drilling has slow rotary speed and does not have temperature increase so that the occurrence of condition such as body tissues burn is avoided.

手动钻孔的钻头转速 慢，无温升，可以避免烧糊人体组织的情况发生。

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Andre Sougarret, mines manager for state-run copper company Codelco and on-site rescue coordinator, said that operation was stopped Tuesday while the drill head was changed.

CNN: STORY HIGHLIGHTS

Martin Siegert points out that the water in the drill head will only be a few degrees above 0C as it enters the lake - it inevitably cools as it flows 3km down into a hole that is surrounded by ice at -35C.

BBC: 'New frontier' of Antarctic lake exploration

Soon after that, I got it in my head to drill my first well.

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