对大口径法兰进行攻丝加工时，攻丝油的选用也相称重要。为了延长丝锥使用寿命，进步螺纹加工质量，应留意以下要点。
The selection of tapping oil is also very important when tapping large diameter flanges. In order to prolong the service life of screw tap and improve the quality of thread processing, we should pay attention to the following points.
攻丝油含有多量氯化物添加剂、活性硫化脂肪油及特别润滑添加剂，由于润滑性特高，能有效地降低切削温度，从而获得很大的切削精度，已成功地应用于各种难加工材料的高难度切削，诸如不锈钢及耐热钢的高速车削、钻孔、攻丝、拉削、滚齿以及刨齿等。
Tapping oil contains a lot of chloride additives, active sulfur fatty oil and special lubricating additives. Because of its high lubricity, it can effectively reduce cutting temperature and thus obtain great cutting accuracy. Tapping oil has been successfully used in high-speed turning and drilling of various difficult-to-machine materials, such as stainless steel and heat-resistant steel. Tapping, broaching, hobbing and gear shaping.
大口径法兰加工时采用不锈钢专用攻丝油效果较好，可直接使用。此外，也可采用攻丝油精和机油自行配置，但配比定要合适。如攻丝油润滑效果不好，则攻出的螺纹光洁度差，且丝锥攻丝阻力大。攻丝油必需具有良好的冷却、润滑和防锈功能。如攻丝油冷却效果不好，则丝锥轻易粘牙，即在丝锥螺纹和前角面上易粘结不锈钢切屑。
The stainless steel special tapping oil has good effect when processing large diameter flange, and it can be used directly. In addition, tapping oil essence and engine oil can be self configured, but the matching ratio should be appropriate. If the oil lubrication effect of tapping is not good, the thread smoothness of the tapping is poor, and the tap tap resistance is large. Tapping oil must have good functions of cooling, lubrication and rust prevention. If the cooling effect of tapping oil is not good, the tap easily sticks to the teeth, that is, stainless steel chip is easily bonded to the tap thread and the front corner surface.