膨胀螺丝底部是磁铁吸住膨胀螺丝底面，到下几部它是怎么套平垫片，弹簧垫片，和螺丝的了。因为都是金属的，这个刚接触就会有吸引的情况，想不通他是怎么克服的？ 视频链接： $("flv_t9o").innerHTML=(mobileplayer() ? "" : AC_FL_RunContent("width", "500", "height", "375", "allowNetworking", "internal", "allowScriptAccess", "never", "src", "https://player.youku.com/player.php/sid/XNTg2NDc4Njcy.html/v.swf", "quality", "high", "bgcolor", "#ffffff", "wmode", "transparent", "allowfullscreen", "true")); （可以点击超清看）