ASME B18.2.1 Square Lag Screws

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