ASME B18.2.1 Square Lag Screws
Dimensions of Square Lag Screws
Nominal Size or Basic product Diameter |
Body or Shoulder Diameter, E |
Width Across Flats, F |
Width Across Corners, G |
Head Height, H |
Minimum Shoulder Length, S |
Radius of Fillet, R |
Max. |
Min. |
Max. |
Min. |
Max. |
Min. |
Max. |
Min. |
Max. |
Min. |
No. 10 |
0.1900 |
0.199 |
0.178 |
0.281 |
0.271 |
0.398 |
0.372 |
0.140 |
0.110 |
0.094 |
0.03 |
0.01 |
1/4 |
0.2500 |
0.260 |
0.237 |
0.375 |
0.362 |
0.530 |
0.498 |
0.188 |
0.156 |
0.094 |
0.03 |
0.01 |
5/16 |
0.3125 |
0.324 |
0.298 |
0.500 |
0.484 |
0.707 |
0.665 |
0.220 |
0.186 |
0.125 |
0.03 |
0.01 |
3/8 |
0.3750 |
0.388 |
0.360 |
0.562 |
0.544 |
0.795 |
0.747 |
0.268 |
0.232 |
0.125 |
0.03 |
0.01 |
7/16 |
0.4375 |
0.452 |
0.421 |
0.625 |
0.603 |
0.884 |
0.828 |
0.316 |
0.278 |
0.156 |
0.03 |
0.01 |
1/2 |
0.5000 |
0.515 |
0.482 |
0.750 |
0.725 |
1.061 |
0.995 |
0.348 |
0.308 |
0.156 |
0.03 |
0.01 |
5/8 |
0.6250 |
0.642 |
0.605 |
0.938 |
0.906 |
1.326 |
1.244 |
0.444 |
0.400 |
0.312 |
0.06 |
0.02 |
3/4 |
0.7500 |
0.768 |
0.729 |
1.125 |
1.088 |
1.591 |
1.494 |
0.524 |
0.476 |
0.375 |
0.06 |
0.02 |
7/8 |
0.8750 |
0.895 |
0.852 |
1.312 |
1.269 |
1.856 |
1.742 |
0.620 |
0.568 |
0.375 |
0.06 |
0.02 |
1 |
1.0000 |
1.022 |
0.976 |
1.500 |
1.450 |
2.121 |
1.991 |
0.684 |
0.628 |
0.625 |
0.09 |
0.03 |
1 1/8 |
1.1250 |
1.149 |
1.098 |
1.688 |
1.631 |
2.386 |
2.239 |
0.780 |
0.720 |
0.625 |
0.09 |
0.03 |
1 1/4 |
1.2500 |
1.277 |
1.223 |
1.875 |
1.812 |
2.652 |
2.489 |
0.876 |
0.812 |
0.625 |
0.09 |
0.03 |