lead screw（丝杠）是什么意思？音标发音+图解场景

丝杠 /ˈliːd ˈskɹuː/ n

English: lead screw · 丝杠

释义：Threaded pointed end for centering the bit in the middle of the hole at the start of drilling.

这个词出现在以下图解场景（1）