铰孔

jiǎo kǒng huò gōng sī shí bù yào yòng lì guò měng yǐ miǎn zhé duàn jiǎo dāo huò sī zhuī

铰孔或攻丝时，不要用力过猛，以免折断铰刀或丝锥。

Do not overexert when reaming holes or threading, lest breaking off the reamer or the tap.