pilot hole

基本解释

First thing you want to do is drill a pilot hole in the right location.
第一件事，你想要做的就是钻一个先导孔在正确的位置。
Each models with a standard-size tabletop fitted with T slots and a precision center pilot hole for alignment and clamping of the fixture or piece parts.
用一个标准尺寸的桌面安装与T插槽和一个中心对准精度先导孔和夹具或夹紧件件每个型号。
When the coil power, the pilot valve by the spring return, pilot hole closed throttle valve chamber pressurized by the piston return spring and thrust, the electromagnetic valve is closed.
当线圈断电时，先导阀芯靠弹簧复位，先导孔关闭，阀腔由活塞节流孔增压和复位弹簧的推力，电磁阀关闭。
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