常用英制螺纹55度,没找到你说的尺寸的螺纹
规格 牙距 成品外径 线径
1/8 40 3.145 -3.030 2.70
5/32 32 3.945-3.795 3.38
3/16 24 4.732 -4.592 4.00
1/4 20 6.320- 6.165 5.45
5/16 18 7.905 -7.737 6.94
3/8 16 9.490 -9.312 8.40
7/16 14 11.07 -10.88 9.84
1/2 12 12.66-12.46 11.22
9/16 12 14.25 -14.04 12.81
5/8 11 15.83 -15.61 14.27