短语词组短語metric plum grub screw 公制無頭梅花螺絲hollow grub screw 平頭空心螺釘conical pointed grub screw 錐形沉頭螺釘;錐耑無頭螺釘hexagon socket grub screw 六角凹頭無頭螺釘grub screw thread 無頭螺釘螺紋lock grub screw 鎖緊螺絲 返回 grub screw