半精螺栓 semi finished bolt

精螺纹级 coarse-thread series ; coarse series thread

微小精密螺丝 MICRO SCREWS

螺纹精度 [机] Accuracy of thread ; tolerance quality

精制螺栓 finished bolt ; turned bolt ; burnished bolt ; [机] bright bolt

精制螺帽 bright nut ; finished nut

特殊精密螺丝 PRECISION AXIS AND SPECIAL FASTENERS

精密螺纹 accurate thread