在室内安装电器设备的动力及照明线路时,必须在水泥墙或砖墙上钉水泥钉。但水泥钉昂贵,且有时用起来不方便。现介绍一种简易方法,可用电钻根据需要选择好锋钢钻头打孔,孔径为7毫米,深度为 When installing electrical power and lighting circuits indoors, cement nails must be nailed to a concrete or brick wall. However, cement nails are expensive and are sometimes inconvenient to use. A simple method is now introduced, which can be used to drill a hole with an electric drill as required. The hole diameter is 7mm and the depth is