Sockets, also known as socket cap, socket head, or socket screws, are a type of threaded fastener and cap screw that have sockets in their head through which torque is applied to screw the fastener. Depending on the type of socket head, a certain tool is required to fasten the screw in place such as a screw driver or Allen wrench.
The most important reasons for the increasing use of socket head cap screws in industry are safety, reliability, and economy.
All three reasons are directly traceable to the superior performance of socket screws vs. other fasteners, and that is due to their superior strength and advanced design
Our socket fasteners can be customized to your application and industry. Please review and download our socket fastener size charts below.
Nominal Size | D | H | X | S | K | F | L | ||||
Head Diameter |
Head Height |
Head Side Height |
Hexagon Socket Size | Key Engage ment |
Fillet Extension | Max Standard Length | |||||
Max | Min | Max | Min | Ref | Nom | Min | Max | Min | Nom | ||
4 5 6 8 |
0.213 0.238 0.262 0.312 |
0.201 0.226 0.250 0.298 |
0.059 0.066 0.073 0.087 |
0.051 0.055 0.063 0.077 |
0.015 0.015 0.015 0.015 |
1/16 5/64 5/64 3/32 |
0.062 0.078 0.078 0.094 |
0.035 0.044 0.044 0.052 |
0.010 0.010 0.010 0.015 |
0.005 0.005 0.005 0.010 |
0.50 0.50 0.63 0.75 |
10 1/4 5/16 3/8 |
0.361 0.437 0.547 0.656 |
0.347 0.419 0.527 0.636 |
0.101 0.132 0.166 0.199 |
0.091 0.122 0.152 0.185 |
0.020 0.031 0.031 0.031 |
1/8 5/32 3/16 7/32 |
0.125 0.156 0.188 0.219 |
0.070 0.087 0.105 0.122 |
0.015 0.020 0.020 0.020 |
0.010 0.015 0.015 0.015 |
1.00 1.00 1.00 1.25 |
1/2 5/8 |
0.875 1.000 |
0.851 0.970 |
0.265 0.331 |
0.245 0.311 |
0.046 0.062 |
5/16 3/8 |
0.312 0.375 |
0.175 0.210 |
0.030 0.030 |
0.020 0.020 |
2.00 2.00 |
Nominal Size | B | D | H | S | K | F | |||
Body Diameter | Head Diameter | Head Height | Hexagon Socket Size | Key Engage- ment |
Fillet Extension Above 0 | ||||
Theo- retical Sharp Max |
Abs Min |
Refer- ence |
Flush- ness Toler- ance |
||||||
Max | Min | Nom | Min | Max | |||||
4 5 6 8 |
0.1120 0.1250 0.1380 0.1640 |
0.1075 0.1202 0.1329 0.1585 |
0.255 0.281 0.307 0.359 |
0.218 0.240 0.263 0.311 |
0.083 0.090 0.097 0.112 |
0.011 0.012 0.013 0.014 |
1/16 5/64 5/64 3/32 |
0.055 0.061 0.066 0.076 |
0.012 0.014 0.015 0.015 |
10 1/4 5/16 3/8 |
0.1900 0.2500 0.3125 0.3750 |
0.1840 0.2435 0.3053 0.3678 |
0.411 0.531 0.656 0.781 |
0.359 0.480 0.600 0.720 |
0.127 0.161 0.198 0.234 |
0.015 0.016 0.017 0.018 |
1/8 5/32 3/16 7/32 |
0.087 0.111 0.135 0.159 |
0.015 0.015 0.015 0.015 |
7/16 1/2 5/8 3/4 |
0.4375 0.5000 0.6250 0.7500 |
0.4294 0.4919 0.6163 0.7406 |
0.844 0.938 1.188 1.438 |
0.781 0.872 1.112 1.355 |
0.234 0.251 0.324 0.396 |
0.018 0.018 0.022 0.024 |
1/4 5/16 3/8 1/2 |
0.159 0.172 0.220 0.220 |
0.015 0.015 0.015 0.015 |
SOCKET HEAD CAP SCREWS | |||||||||||||
Basic Screw Diam. | D |
A |
H |
C |
J |
T |
G |
K | |||||
Body Diameter | Head Diameter | Head Height | Top Chamfer or Radius | Hexagon Socket Size and Width Across Flats | Key Engage-ment | Wall Thick-ness | Bottom Chamfer or Radius | ||||||
Max | Min | Max | Min | Max | Min | Min | Nom | Max | Min | Min | Min | Max | |
0 | 0.0600 | 0.0568 | 0.096 | 0.091 | 0.060 | 0.057 | 0.004 | 0.050 | 0.0510 | 0.0500 | 0.025 | 0.020 | 0.007 |
1 | 0.0730 | 0.0695 | 0.118 | 0.112 | 0.073 | 0.070 | 0.005 | 1/16 | 0.0635 | 0.0635 | 0.031 | 0.025 | 0.007 |
2 | 0.0860 | 0.0822 | 0.140 | 0.134 | 0.086 | 0.083 | 0.008 | 5/64 | 0.0791 | 0.0781 | 0.038 | 0.029 | 0.007 |
3 | 0.0990 | 0.0949 | 0.161 | 0.154 | 0.099 | 0.095 | 0.008 | 5/64 | 0.0791 | 0.0781 | 0.044 | 0.034 | 0.007 |
4 | 0.1120 | 0.1075 | 0.183 | 0.176 | 0.112 | 0.108 | 0.009 | 3/32 | 0.0952 | 0.0937 | 0.051 | 0.038 | 0.008 |
5 | 0.1250 | 0.1202 | 0.205 | 0.198 | 0.125 | 0.121 | 0.012 | 3/32 | 0.0952 | 0.0937 | 0.057 | 0.043 | 0.008 |
6 | 0.1380 | 0.1329 | 0.226 | 0.218 | 0.138 | 0.134 | 0.013 | 7/64 | 0.1111 | 0.1094 | 0.064 | 0.047 | 0.008 |
8 | 0.1640 | 0.1585 | 0.270 | 0.262 | 0.164 | 0.159 | 0.014 | 9/64 | 0.1426 | 0.1406 | 0.077 | 0.056 | 0.008 |
10 | 0.1900 | 0.1840 | 0.312 | 0.303 | 0.190 | 0.185 | 0.016 | 5/32 | 0.1587 | 0.1562 | 0.090 | 0.065 | 0.008 |
1/4 | 0.2500 | 0.2435 | 0.375 | 0.365 | 0.250 | 0.244 | 0.025 | 3/16 | 0.1900 | 0.1875 | 0.120 | 0.095 | 0.010 |
5/16 | 0.3125 | 0.3053 | 0.469 | 0.457 | 0.312 | 0.306 | 0.033 | 1/4 | 0.2530 | 0.2500 | 0.151 | 0.119 | 0.010 |
3/8 | 0.3750 | 0.3678 | 0.562 | 0.550 | 0.375 | 0.368 | 0.040 | 5/16 | 0.3160 | 0.3125 | 0.182 | 0.143 | 0.010 |
7/16 | 0.4375 | 0.4294 | 0.656 | 0.642 | 0.438 | 0.430 | 0.047 | 3/8 | 0.3790 | 0.3750 | 0.213 | 0.166 | 0.010 |
1/2 | 0.5000 | 0.4919 | 0.750 | 0.735 | 0.500 | 0.492 | 0.055 | 3/8 | 0.3790 | 0.3750 | 0.245 | 0.190 | 0.015 |
5/8 | 0.6250 | 0.6163 | 0.938 | 0.921 | 0.625 | 0.616 | 0.070 | 1/2 | 0.5050 | 0.5000 | 0.307 | 0.238 | 0.015 |
3/4 | 0.7500 | 0.7406 | 1.125 | 1.107 | 0.750 | 0.740 | 0.085 | 5/8 | 0.6310 | 0.6250 | 0.370 | 0.285 | 0.015 |
7/8 | 0.8750 | 0.8647 | 1.312 | 1.293 | 0.875 | 0.864 | 0.100 | 3/4 | 0.7570 | 0.7500 | 0.432 | 0.333 | 0.020 |
1 | 1.0000 | 0.9886 | 1.500 | 1.479 | 1.000 | 0.988 | 0.114 | 3/4 | 0.7570 | 0.7500 | 0.495 | 0.380 | 0.020 |
1 1/4 | 1.2500 | 1.2336 | 1.875 | 1.852 | 1.250 | 1.236 | 0.144 | 7/8 | 0.8850 | 0.8750 | 0.620 | 0.475 | 0.020 |
1 1/2 | 1.5000 | 1.4818 | 2.250 | 2.224 | 1.500 | 1.485 | 0.176 | 1 | 1.0100 | 1.0000 | 0.745 | 0.570 | 0.020 |
Tolerance on Length | Nominal Screw Size | Nominal Screw Length | |||||||||||
Up to 1 in., Incl. | Over 1 in. to 2-1/2 in., Incl. | Over 2-1/2 to 6 in., Incl. | Over 6 in. | ||||||||||
0 thru 3/8, Incl. | -0.03 | -0.04 | -0.06 | -0.12 | |||||||||
7/16 thru 3/4, Incl. | -0.03 | -0.06 | -0.08 | -0.12 | |||||||||
7/8 thru 1-1/2, Incl. | -0.05 | -0.10 | -0.14 | -0.20 |
Nominal Size | B | D | H | S | K | F | ||||
Basic Screw Diameter |
Head Diameter | Head Height | Socket Size | Engage- ment |
Fillet | |||||
Max | Min | Max | Min | Min | Max | Min | ||||
8 10 1/4 5/16 |
0.1640 0.1900 0.2500 0.3125 |
.270 .312 .375 .437 |
.265 .307 .369 .431 |
.082 .095 .125 .156 |
.079 .092 .121 .152 |
.0781 .0938 .1250 .1562 |
.060 .072 .094 .120 |
.012 .014 .014 .017 |
.007 .009 .009 .012 |
|
3/8 7/16 1/2 |
0.3750 0.4375 0.5000 |
.562 .625 .750 |
.556 .618 .743 |
.187 .218 .250 |
.182 .213 .244 |
.1875 .2188 .2500 |
.145 .166 .184 |
.020 .023 .026 |
.015 .018 .020 |
Nominal Key Size |
F | C | S | L | R | K | ||||||
Hexagon Width Across Flats | Hexagon Width Across Corner |
Length of Short Arm |
Length of Long Arm | Radius of Bend |
Chamfer | |||||||
Short Series | Long Series | |||||||||||
Max | Min | Max | Min | Max | Min | Max | Min | Max | Min | Min | Max | |
0.028 0.035 0.050 1/16 |
0.0280 0.0350 0.0500 0.0625 |
0.0275 0.0345 0.0490 0.0615 |
0.0314 0.0393 0.0560 0.0701 |
0.0300 0.0378 0.0540 0.0680 |
0.312 0.438 0.625 0.656 |
0.125 0.250 0.438 0.469 |
1.312 1.312 1.750 1.844 |
1.125 1.125 1..562 1.656 |
2.688 2.766 2.938 3.094 |
2.500 2.578 2.750 2.906 |
0.062 0.062 0.062 0.062 |
0.003 0.004 0.006 0.008 |
5/64 3/32 7/64 1/8 |
0.0781 0.0937 0.1094 0.1250 |
0.0771 0.0927 0.1079 0.1235 |
0.0880 0.1058 0.1238 0.1418 |
0.0859 0.1035 0.1210 0.1390 |
0.703 0.750 0.797 0.844 |
0.516 0.562 0.609 0.656 |
1.969 2.094 2.219 2.344 |
1.781 1.906 2.031 2.156 |
3.281 3.469 3.656 3.844 |
3.094 3.281 3.469 3.656 |
0.078 0.094 0.109 0.125 |
0.008 0.009 0.014 0.015 |
9/64 5/32 3/16 7/32 |
0.1406 0.1562 0.1875 0.2187 |
0.1391 0.1547 0.1860 0.2172 |
0.1593 0.1774 0.2135 0.2490 |
0.1566 0.1745 0.2105 0.2460 |
0.891 0.938 1.031 1.125 |
0.703 0.750 0.844 0.938 |
2.469 2.594 2.844 3.094 |
2.281 2.406 2.656 2.906 |
4.031 4.219 4.594 4.969 |
3.844 4.031 4.406 4.781 |
0.141 0.156 0.188 0.219 |
0.016 0.016 0.022 0.024 |
1/4 5/16 3/8 7/16 |
0.2500 0.3125 0.3750 0.4375 |
0.2485 0.3110 0.3735 0.4355 |
0.2845 0.3570 0.4285 0.5005 |
0.2815 0.3531 0.4238 0.4944 |
1.219 1.344 1.469 1.594 |
1.031 1.156 1.281 1.406 |
3.344 3.844 4.344 4.844 |
3.156 3.656 4.156 4.656 |
5.344 6.094 6.844 7.594 |
5.156 5.906 6.656 7.406 |
0.250 0.312 0.375 0.438 |
0.030 0.032 0.044 0.047 |
1/2 9/16 5/8 3/4 |
0.5000 0.5625 0.6250 0.7500 |
0.4975 0.5600 0.6225 0.7470 |
0.5715 0.6420 0.7146 0.8580 |
0.5650 0.6356 0.7080 0.8512 |
1.719 1.844 1.969 2.219 |
1.531 1.656 1.781 2.031 |
5.344 5.844 6.344 7.344 |
5.156 5.656 6.156 7.156 |
8.344 9.094 9.844 11.344 |
8.156 8.906 9.656 11.156 |
0.500 0.562 0.625 0.750 |
0.050 0.053 0.055 0.070 |
7/8 1 |
0.8750 1.0000 |
0.8720 0.9970 |
1.0020 1.1470 |
0.9931 1.1350 |
2.469 2.719 |
2.281 2.531 |
8.344 9.344 |
8.156 9.156 |
12.844 14.344 |
12.656 14.156 |
0.875 1.000 |
0.076 0.081 |
Nominal Size | O | Threads Per Inch | S | K | W | L | Tightening Torque (Inch-Lbs.) |
|
Nominal O.D. |
Hex Socket Size |
Key Engage- ment |
Wall Thickness |
Overall Length | ||||
Min | Min | Max | Min | |||||
1/16 1/8 1/4 3/8 |
0.307 0.401 0.529 0.667 |
27 27 18 18 |
5/32 3/16 1/4 5/16 |
.140 .140 .218 .250 |
.052 .049 .045 .040 |
.250 .250 .406 .406 |
.235 .235 .391 .391 |
150 250 600 1200 |
1/2 3/4 1 1-1/4 |
0.830 1.041 1.302 1.647 |
14 14 11-1/2 11-1/2 |
3/8 9/16 5/8 3/4 |
.312 .312 .375 .437 |
.067 .054 .112 .102 |
.531 .531 .656 .656 |
.516 .516 .641 .641 |
1800 3000 4200 5400 |
Nominal Size | O | Threads Per Inch | S | K | W | L | Tightening Torque (Inch-Lbs.) |
|
Nominal O.D. |
Hex Socket Size |
Key Engage- ment |
Wall Thickness |
Overall Length | ||||
Min | Min | Max | Min | |||||
1/16 1/8 1/4 3/8 1/2 |
0.3120 0.4050 0.5400 0.6750 0.8400 |
27 27 18 18 14 |
5/32 3/16 1/4 5/16 3/8 |
.1400 .1400 .2180 .2500 .3120 |
.0620 .0620 .0730 .0840 .0950 |
.3240 .3240 .4570 .5200 .5820 |
.3000 .3000 .4170 .4800 .5420 |
150 250 600 1200 1800 |
3/4 1 1-1/4 1-1/2 2 |
1.0500 1.3150 1.6600 1.9000 2.3750 |
14 11-1/2 11-1/2 11-1/2 11-1/2 |
9/16 5/8 3/4 1 1 |
.3120 .3750 .4370 .4370 .4370 |
.1250 .1250 .1560 .1560 .1560 |
.6450 .7700 .8320 .8430 .9060 |
.6050 .7300 .7920 .7800 .8440 |
3000 4200 5400 6900 8500 |
Nominal Size | A | D | H | Z | S | K | E | F | |||
Shoulder Diameter |
Head Diameter | Head Height | Head Side Height |
Hexagon Socket Size |
Key Engage- ment |
Head Fillet Extension Above D |
Head Fillet Radius |
||||
Max | Min | Max | Min | Max | Min | Min | Nom | Min | Max | Min | |
1/4 5/16 3/8 |
0.2480 0.3105 0.3730 |
0.2460 0.3085 0.3710 |
0.375 0.438 0.562 |
0.357 0.419 0.543 |
0.188 0.219 0.250 |
0.177 0.209 0.240 |
0.157 0.183 0.209 |
1/8 5/32 3/16 |
0.094 0.117 0.141 |
0.014 0.017 0.020 |
0.009 0.012 0.015 |
1/2 5/8 3/4 |
0.4980 0.6230 0.7480 |
0.4960 0.6210 0.7460 |
0.750 0.875 1.000 |
0.729 0.853 0.977 |
0.312 0.375 0.500 |
0.302 0.365 0.490 |
0.262 0.315 0.421 |
1/4 5/16 3/8 |
0.188 0.234 0.281 |
0.026 0.032 0.039 |
0.020 0.024 0.030 |
Nominal Size | N | W | T | L | Q | C | B | |||
Shoulder Neck Diameter |
Shoulder Neck Width | Nominal Thread Size |
Threads Per In. | Thread Neck Diameter | Thread Neck | Thread Neck Fillet | Thread Length |
|||
Min | Max | Max | Min | Max | Max | Min | Basic | |||
1/4 5/16 3/8 |
0.227 0.289 0.352 |
0.093 0.093 0.093 |
10 1/4 5/16 |
24 20 18 |
0.142 0.193 0.249 |
0.133 0.182 0.237 |
0.083 0.100 0.111 |
0.023 0.028 0.031 |
0.017 0.022 0.025 |
0.375 0.438 0.500 |
1/2 5/8 3/4 |
0.477 0.602 0.727 |
0.093 0.093 0.093 |
3/8 1/2 5/8 |
16 13 11 |
0.304 0.414 0.521 |
0.291 0.397 0.502 |
0.125 0.154 0.182 |
0.035 0.042 0.051 |
0.029 0.036 0.045 |
0.625 0.750 0.875 |
Nominal Size | S | K | F | 0 | D | H | A | ||||||||
Hexagon Socket Size | Min Key Engage- ment |
Cup & Flat Point Diameter | Oval Point Radius |
Half Dog Point | Shortest Length To Which K Applies | Cone Pt. Angle 90° For These Lengths or Longer |
|||||||||
Diameter | Length | Cup & Flat Points |
90° Cone & Oval Pts. |
Half Dog Point |
|||||||||||
Nom | Min | Max | Min | Basic | Max | Min | Max | Min | |||||||
4 5 6 8 |
0.050 1/16 1/16 5/64 |
0.070 0.080 0.080 0.090 |
0.061 0.067 0.074 0.087 |
0.051 0.057 0.064 0.076 |
0.084 0.094 0.104 0.123 |
0.075 0.083 0.092 0.109 |
0.070 0.078 0.087 0.103 |
0.030 0.033 0.038 0.043 |
0.026 0.027 0.032 0.037 |
0.19 0.19 0.19 0.19 |
0.19 0.19 0.25 0.25 |
0.19 0.19 0.19 0.25 |
0.19 0.19 0.19 0.25 |
||
10 1/4 5/16 3/8 |
3/32 1/8 5/32 3/16 |
0.100 0.125 0.156 0.188 |
0.102 0.132 0.172 0.212 |
0.088 0.118 0.156 0.194 |
0.142 0.188 0.234 0.281 |
0.127 0.156 0.203 0.250 |
0.120 0.149 0.195 0.241 |
0.049 0.067 0.082 0.099 |
0.041 0.059 0.074 0.089 |
0.19 0.25 0.31 0.38 |
0.25 0.31 0.44 0.44 |
0.25 0.31 0.38 0.44 |
0.25 0.31 0.38 0.44 |
||
7/16 1/2 5/8 3/4 |
7/32 1/4 5/16 3/8 |
0.219 0.250 0.312 0.375 |
0.252 0.291 0.371 0.450 |
0.232 0.270 0.347 0.425 |
0.328 0.375 0.469 0.562 |
0.297 0.344 0.469 0.562 |
0.287 0.334 0.456 0.549 |
0.114 0.130 0.164 0.196 |
0.104 0.120 0.148 0.180 |
0.44 0.50 0.63 0.75 |
0.63 0.63 0.88 1.00 |
0.50 0.63 0.88 1.00 |
0.50 0.57 0.75 0.88 |
||
7/8 1 |
1/2 9/16 |
0.500 0.562 |
0.530 0.609 |
0.502 0.579 |
0.656 0.750 |
0.656 0.750 |
0.642 0.734 |
0.227 0.260 |
0.211 0.240 |
0.88 1.00 |
1.00 1.25 |
1.00 1.25 |
1.00 1.13 |