用短钻头先钻浅孔，然后把稍长钻头放入孔中后夹紧接着钻，再换更长钻头放入孔中，夹紧，接着钻，直到9”深，需多个钻头

来源: osch1130 于 2023-04-05 19:09:50 [旧帖] [给我悄悄话] 本文已被阅读：次

WENXUECITY.COM does not represent or guarantee the truthfulness, accuracy, or reliability of any of communications posted by other users.