An internal polygonal is arranged on the top of the hex nut; diameter of the internal polygonal matches with the diameter of an internal polygonal screwtool.
又在六角螺帽顶端设置内多角，其径与内多角螺丝工具直径相适应。
2
Unscrew the screw (3) with Allen key, and take out the external skive tool.
用随机附送的内六角扳手松开螺丝(3)，拿出外剥刀具。
3
Based on this, we may make improvement to prolong the life of screw drill tool and screw pump.