我矿机修車間在铸鉄瓦皮上挂五金瓦时,由于鑄鉄与钨金不易結合,所以要在鑄鉄瓦皮上鑽出一些倒退拔孔(即使孔成为大头小尾的形狀),以拉住鎢金,保証挂鎢金瓦的質量。为了加工这倒退拔孔,楊玉民同志改进了一种刀具。这刀具的結構如图1。图中:1是刀杆,一端开有一个槽、并在侧面鑽 When mine machine repair workshop hangs the metal tile on the casting tile tile, because the casting tile and the tungsten alloy are not easy to be combined, we should drill back a few holes on the tile casting tile (even if the hole becomes the shape of big tail), pull Tungsten living, to ensure the quality of tungsten tile hanging. In order to process this retrogression, Comrade Yang Yumin improved a knife. The structure of this tool is shown in Figure 1. In the picture: 1 is a cutter bar, a groove is opened at one end, and the side is drilled