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ASME B18.2.1 Hex Cap Screws

ASME B18.2.1 Hex Cap Screws

Dimensions of ASME B18.2.1 Hex Cap Screws

Nominal Size or Basic product Diameter Body Diameter, E Width Across Flats, F Width Across Corners, G Head Height, H Minimum Wrenching Height, J Thread Length for Screws Lengths, LT Transition Thread Length, Y Maximum Total Runout of Bearing Surface FIM
6 in. & Shorter Over 6 in.
Max. Min. Basic Max. Min. Max. Min. Basic Max. Min. Nom. Nom.
1/4
0.2500
0.2500 0.2450 7/16 0.438 0.428 0.505 0.488 5/32 0.163 0.150 0.106 0.750 1.000 0.250 0.010
5/16
0.3125
0.3125 0.3065 1/2 0.500 0.489 0.577 0.557 13/64 0.211 0.195 0.140 0.875 1.125 0.278 0.011
3/8
0.3750
0.3750 0.3690 9/16 0.562 0.551 0.650 0.628 15/64 0.243 0.226 0.160 1.000 1.250 0.312 0.012
7/16
0.4375
0.4375 0.4305 5/8 0.625 0.612 0.722 0.698 9/32 0.291 0.272 0.195 1.125 1.375 0.357 0.013
1/2
0.5000
0.5000 0.4930 3/4 0.750 0.736 0.866 0.840 5/16 0.323 0.302 0.215 1.250 1.500 0.385 0.014
9/16
0.5625
0.5625 0.5545 13/16 0.812 0.798 0.938 0.910 23/64 0.371 0.348 0.250 1.375 1.625 0.417 0.015
5/8
0.6250
0.6250 0.6170 15/16 0.938 0.922 1.083 1.051 25/64 0.403 0.378 0.269 1.500 1.750 0.455 0.017
3/4
0.7500
0.7500 0.7410 1 1/8 1.125 1.100 1.299 1.254 15/32 0.483 0.455 0.324 1.750 2.000 0.500 0.020
7/8
0.8750
0.8750 0.8660 1 5/16 1.312 1.285 1.516 1.465 35/64 0.563 0.531 0.378 2.000 2.250 0.556 0.023
1
1.0000
1.000 0.9900 1 1/2 1.500 1.469 1.732 1.675 39/64 0.627 0.591 0.416 2.250 2.500 0.625 0.026
1 1/8
1.1250
1.1250 1.1140 1 11/16 1.688 1.631 1.949 1.859 11/16 0.718 0.658 0.461 2.500 2.750 0.714 0.029
1 1/4
1.2500
1.2500 1.2390 1 7/8 1.875 1.812 2.165 2.066 25/32 0.813 0.749 0.530 2.750 3.000 0.714 0.033
1 3/8
1.3750
1.3750 1.3630 2 1/16 2.062 1.994 2.382 2.273 27/32 0.878 0.810 0.569 3.000 3.250 0.833 0.036
1 1/2
1.5000
1.5000 1.4880 2 1/4 2.250 2.175 2.598 2.480 15/16 0.974 0.902 0.640 3.250 3.500 0.833 0.039
1 5/8
1.6250
1.6250 1.6130 2 7/16 2.438 2.356 2.815 2.686 1 1.038 0.962 0.694 3.500 3.750 0.909 0.043
1 3/4
1.7500
1.7500 1.7380 2 5/8 2.625 2.538 3.031 2.893 1 3/32 1.134 1.054 0.748 3.750 4.000 1.000 0.046
1 7/8
1.8750
1.8750 1.8630 2 13/16 2.812 2.719 3.248 3.099 1 5/32 1.198 1.114 0.802 4.000 4.250 1.000 0.049
2
2.000
2.000 1.9880 3 3.000 2.900 3.464 3.306 1 7/32 1.263 1.175 0.825 4.250 4.500 1.111 0.052
2 1/4
2.2500
2.2500 2.2380 3 3/8 3.375 3.262 3.897 3.719 1 3/8 1.423 1.327 0.933 -- 5.000 1.111 0.059
2 1/2
2.5000
2.5000 2.4880 3 3/4 3.750 3.625 4.330 4.133 1 17/32 1.583 1.479 1.042 -- 5.500 1.250 0.065
2 3/4
2.7500
2.7500 2.7380 4 1/8 4.125 3.988 4.763 4.546 1 11/16 1.744 1.632 1.151 -- 6.000 1.250 0.072
3
3.000
3.000 2.9880 4 1/2 4.500 4.350 5.196 4.959 1 7/8 1.935 1.815 1.290 -- 6.500 1.250 0.079