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，你想要做的就是鑽一個先導孔在正確的位置。
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.
用一個標準尺寸的桌麪安裝與T插槽和一個中心對準精度先導孔和夾具或夾緊件件每個型號。
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.
儅線圈斷電時，先導閥芯靠彈簧複位，先導孔關閉，閥腔由活塞節流孔增壓和複位彈簧的推力，電磁閥關閉。
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