
| Nominal size D |
Number of threads per inch |
Width across flats A |
Approx. max. width across corners C |
Thickness of nut E |
Thickness of nut F |
Tolerance for squareness of thread to face of nut (see Clause 10) |
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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Faced one side | Faced both side |
Black | Faced both side |
Black | Machined | ||||||||||
| B.S.W | B.S.F | max. | min. | Hexagon. | square. | min. | max. | min. | max. | min. | max. | min. | max. | max. | |
| in. | in. | in. | in. | in. | in. | in. | in. | in. | in. | in. | in. | in. | in. | ||
| ¼ | 20 | 26 | 0.445 | 0.435 | 0.51 | 0.63 | 0.180 | 0.200 | 0.190 | 0.185 | 0.180 | -- | -- | 0.014 | 0.007 |
| ⁵⁄₁₆ | 18 | 22 | 0.525 | 0.515 | 0.61 | 0.74 | 0.230 | 0.250 | 0.240 | 0.210 | 0.200 | -- | -- | 0.018 | 0.009 |
| ⅜ | 16 | 20 | 0.600 | 0.585 | 0.69 | 0.85 | 0.292 | 0.312 | 0.302 | 0.260 | 0.250 | -- | -- | 0.020 | 0.010 |
| ⁷⁄₁₆ | 14 | 18 | 0.710 | 0.695 | 0.82 | 1.00 | 0.355 | 0.375 | 0.365 | 0.275 | 0.265 | -- | -- | 0.022 | 0.011 |
| ½ | 12 | 16 | 0.820 | 0.800 | 0.95 | 1.16 | 0.417 | 0.437 | 0.427 | 0.300 | 0.290 | -- | -- | 0.026 | 0.013 |
| ⁹⁄₁₆ | 12 | 16 | 0.920 | 0.900 | 1.06 | 1.30 | 0.480 | 0.500 | 0.490 | 0.333 | 0.323 | -- | -- | 0.026 | 0.013 |
| ⅝ | 11 | 14 | 1.010 | 0.985 | 1.17 | 1.43 | 0.542 | 0.562 | 0.552 | 0.410 | 0.375 | 0.375 | 0.365 | 0.028 | 0.014 |
| ¾ | 10 | 12 | 1.200 | 1.175 | 1.39 | 1.70 | 0.668 | 0.687 | 0.677 | 0.490 | 0.458 | 0.448 | 0.448 | 0.034 | 0.017 |
| ⅞ | 9 | 11 | 1.300 | 1.270 | 1.50 | 1.84 | 0.720 | 0.750 | 0.740 | 0.550 | 0.500 | 0.500 | 0.490 | 0.040 | 0.020 |
| 1 | 8 | 10 | 1.480 | 1.450 | 1.71 | 2.09 | 0.835 | 0.875 | 0.865 | 0.630 | 0.583 | 0.583 | 0.573 | 0.040 | 0.020 |
| 1⅛ | 7 | 9 | 1.670 | 1.640 | 1.93 | 2.36 | 0.960 | 1.000 | 0.990 | 0.720 | 0.666 | 0.666 | 0.656 | 0.048 | 0.024 |
| 1¼ | 7 | 9 | 1.860 | 1.815 | 215 | 2.63 | 1.080 | 1.125 | 1.105 | 0.810 | 0.750 | 0.750 | 0.730 | 0.048 | 0.024 |
| 1⅜a | 6 | 8 | 2.050 | 2.005 | 2.37 | 2.90 | 1.190 | 1.250 | 1.230 | 0.890 | 0.833 | 0.833 | 0.813 | 0.052 | 0.026 |
| 1½ | 6 | 8 | 2.220 | 2.175 | 2.56 | 3.14 | 1.315 | 1.375 | 1.355 | 0.980 | 0.916 | 0.916 | 0.896 | 0.052 | 0.026 |
| 1⅝a | 5 | 8 | 2.410 | 2.365 | 2.78 | 3.41 | 1.440 | 1.500 | 1.480 | 1.060 | 1.000 | 1.000 | 0.980 | 0.052 | 0.026 |
| 1¾ | 5 | 7 | 2.580 | 2.520 | 2.98 | 3.65 | 1.565 | 1.625 | 1.605 | 1.160 | 1.083 | 1.083 | 1.063 | 1.060 | 1.030 |
| 2 | 4.5 | 7 | 2.760 | 2.700 | 3.19 | 3.90 | 1.690 | 1.750 | 1.730 | 1.250 | 1.166 | 1.166 | 1.146 | 0.060 | 0.030 |
| 2¼ | 4 | 6 | 3.150 | 3.090 | 3.64 | 4.45 | 1.815 | 1.875 | 1.855 | 1.430 | 1.250 | 1.250 | 1.229 | 0.060 | 0.030 |
| 2½ | 4 | 6 | 3.550 | 3.490 | 4.10 | 5.02 | 2.065 | 2.125 | 2.105 | 1.600 | 1.416 | 1.416 | 1.396 | 0.070 | 0.035 |
| 2¾ | 3.5 | 6 | 3.830 | 3.830 | 4.49 | 5.50 | 2.315 | 2.375 | 2.355 | 1.770 | 1.580 | 1.580 | 1.560 | 0.070 | 0.035 |
| 3 | 3.5 | 5 | 4.180 | 4.080 | 4.83 | 5.91 | 2.525 | 2.625 | 2.605 | 1.980 | 1.750 | 1.750 | 1.730 | 0.080 | 0.040 |
| 3¼a | 3.25 | 5 | 4.530 | 4.430 | 5.23 | 6.41 | 2.775 | 2.875 | 2.845 | 2.150 | 1.915 | 1.915 | 1.882 | 0.080 | 0.040 |
| 3½ | 3.25 | 4.5 | 4.850 | 4.750 | 5.60 | 6.86 | 3.025 | 3.125 | 3.095 | 2.320 | 2.083 | 2.083 | 2.051 | 2.090 | 2.045 |
| 3¾a | 3 | 4.5 | 5.180 | 5.080 | 5.98 | 7.33 | 3.275 | 3.375 | 3.345 | 2.480 | 2.250 | 2.250 | 2.212 | 0.090 | 0.045 |
| 4 | 3 | 4.5 | 5.550 | 5.450 | 6.41 | 7.85 | 3.525 | 3.625 | 3.595 | 2.650 | 2.417 | 2.417 | 2.387 | 0.100 | 0.050 |
| 4½ | 2.875 | 4 | 6.380 | 6.255 | 7.37 | 9.02 | 3.850 | 4.000 | 3.970 | 3.030 | 2.666 | 2.666 | 2.636 | 0.110 | 0.055 |
| 5 | 2.750 | 4 | 7.300 | 7.175 | 8.43 | 10.32 | 4.350 | 4.500 | 4.470 | 3.370 | 3.000 | 3.000 | 2.970 | 0.120 | 0.060 |
| 5½ | 2.625 | 4 | 8.350 | 8.225 | 9.64 | 11.81 | 4.850 | 5.000 | 4.970 | 3.700 | 3.333 | 3.333 | 3.303 | 0.130 | 0.065 |
| 6 | 2.500 | 4 | 9.450 | 9.325 | 10.91 | 13.36 | 5.350 | 5.500 | 5.470 | 4.030 | 3.666 | 3.666 | 3.636 | 0.140 | 0.070 |
| a To be dispensed with wherever possible. The dimensions of black lock nuts in the above table are designed to permit the product to be manufactured by either hot forging. cold forming or cold pressing, at the option of the manufacturer. |
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