这类钻头可以有三条或四条出屑槽及相同数量的保证良好导向的导向边，这样使得加工有高精度。

This type of drill may have either three or four flutes and equal number of margins, which ensure superior guidance, thus resulting in high machining accuracy.

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自攻干墙螺丝，平头十字槽，钻头，镀锌。

Self drywall screws, Pan head Phillips, Drill point, zinc.

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在结构上采用了三翼四齿的钻头体、弧槽形排粉沟槽，适用于硬、中硬、软岩的三种齿形。

The drill bit body has three wings four cylindrical tungsten carbide inserts and curved slots for removal of cuttings.

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