
Dimensions of Square and Hex Machine Screw Nuts
| Nominal or Basic Major Diameter Thread |
F | G | G1 | Thickness | Bearing Surface, Runout to Thread Axis, FIM |
|||||
| Width Across Flats | Width Across Corners | |||||||||
| Square | Hex | |||||||||
| Basic | Max | Min | Max | Min | Max | Min | Max | Min | ||
| 0 (0.060) | 5/32 | 0.156 | 0.150 | 0.221 | 0.206 | 0.180 | 0.171 | 0.050 | 0.043 | 0.005 |
| 1 (0.073) | 5/32 | 0.156 | 0.150 | 0.221 | 0.206 | 0.180 | 0.171 | 0.050 | 0.043 | 0.005 |
| 2 (0.086) | 3/16 | 0.188 | 0.180 | 0.265 | 0.247 | 0.217 | 0.205 | 0.066 | 0.057 | 0.006 |
| 3 (0.099) | 3/16 | 0.188 | 0.180 | 0.265 | 0.247 | 0.217 | 0.205 | 0.066 | 0.057 | 0.006 |
| 4 (0.112) | 1/4 | 0.250 | 0.241 | 0.354 | 0.331 | 0.289 | 0.275 | 0.098 | 0.087 | 0.009 |
| 5 (0.125) | 5/16 | 0.312 | 0.302 | 0.442 | 0.415 | 0.361 | 0.344 | 0.114 | 0.102 | 0.011 |
| 6 (0.138) | 5/16 | 0.312 | 0.302 | 0.442 | 0.415 | 0.361 | 0.344 | 0.114 | 0.102 | 0.011 |
| 8 (0.164) | 11/32 | 0.344 | 0.332 | 0.486 | 0.456 | 0.397 | 0.378 | 0.130 | 0.117 | 0.012 |
| 10 (0.190) | 3/8 | 0.375 | 0.362 | 0.53 | 0.497 | 0.433 | 0.413 | 0.130 | 0.117 | 0.013 |
| 12 (0.216) | 7/16 | 0.438 | 0.423 | 0.619 | 0.581 | 0.505 | 0.482 | 0.161 | 0.148 | 0.015 |
| 1/4 (0.250) | 7/16 | 0.438 | 0.423 | 0.619 | 0.581 | 0.505 | 0.482 | 0.193 | 0.178 | 0.015 |
| 5/16 (0.312) | 9/16 | 0.562 | 0.545 | 0.795 | 0.748 | 0.65 | 0.621 | 0.225 | 0.208 | 0.020 |
| 3/8 (0.375) | 5/8 | 0.625 | 0.607 | 0.884 | 0.833 | 0.722 | 0.692 | 0.257 | 0.239 | 0.021 |