1/4" Short Arm Hex Import = HKS1/4 1/4" Short Arm Hex Domestic = HKS1/4D
2" Long Arm Hex Import = HKL2 2" Long Arm Hex Domestic = HKL2D
Less than 3/8 - HRC 48 Min
Greater than or equal to 3/8 - HRC 45 Min
| F | C | S | L | R | K | ||||||
| Key Size Across Flats | Across Corners | Short Arm | Long Arm | Radius | Chamfer | ||||||
| Short Series | Long Series | ||||||||||
| Max | Min | Max | Min | Max | Min | Max | Min | Max | Min | Min | Max |
| 0.0280 | 0.0275 | 0.0314 | 0.0300 | 0.312 | 0.125 | 1.312 | 1.125 | 2.688 | 2.500 | 0.062 | 0.003 |
| 0.0350 | 0.0345 | 0.0393 | 0.0378 | 0.438 | 0.250 | 1.312 | 1.125 | 2.766 | 2.578 | 0.062 | 0.004 |
| 0.0500 | 0.0490 | 0.0560 | 0.0540 | 0.625 | 0.438 | 1.750 | 1.562 | 2.938 | 2.750 | 0.062 | 0.006 |
| 1/16 | 0.0615 | 0.0701 | 0.0680 | 0.656 | 03469 | 1.844 | 1.656 | 3.094 | 2.906 | 0.062 | 0.008 |
| 5/64 | 0.0771 | 0.0880 | 0.0859 | 0.703 | 0.516 | 1.969 | 1.781 | 3.281 | 3.094 | 0.078 | 0.008 |
| 3/32 | 0.0927 | 0.1058 | 0.1035 | 0.750 | 0.562 | 2.904 | 1.906 | 3.469 | 3.281 | 0.094 | 0.009 |
| 7/64 | 0.1079 | 0.1238 | 0.1210 | 0.797 | 0.609 | 2.219 | 2.031 | 3.656 | 6.469 | 0.109 | 0.014 |
| 1/8 | 0.1235 | 0.1418 | 0.1390 | 0.844 | 0.656 | 2.344 | 2.156 | 3.844 | 3.656 | 0.125 | 0.015 |
| 9/64 | 0.1391 | 0.1593 | 0.1566 | 0.891 | 0.703 | 2.469 | 2.281 | 4.031 | 3.844 | 0.141 | 0.016 |
| 5/32 | 0.1547 | 0.1774 | 0.1745 | 0.938 | 0.750 | 2.594 | 2.406 | 4.219 | 4.031 | 0.156 | 0.016 |
| 3/16 | 0.1860 | 0.2135 | 0.2105 | 1.031 | 0.844 | 2.844 | 2.656 | 4.594 | 4.406 | 0.188 | 0.022 |
| 7/32 | 0.2718 | .2490 | 0.2460 | 1.125 | 0.938 | 3.094 | 2.906 | 4.969 | 4.781 | 0.219 | 0.024 |
| 1/4 | 0.2485 | 0.2845 | 0.2815 | 1.219 | 1.031 | 3.344 | 3.156 | 5.344 | 5.156 | 0.250 | 0.030 |
| 5/31 | 0.3110 | 0.3570 | 0.3531 | 1.344 | 1.156 | 3.844 | 3.656 | 6.094 | 5.906 | 0.312 | 0.032 |
| 3/8 | 0.3735 | 0.4285 | 0.4238 | 1.469 | 1.281 | 4.344 | 4.156 | 6.844 | 6.656 | 0.375 | 0.044 |
| 7/16 | 0.4355 | 0.5005 | 0.4944 | 1.594 | 1.406 | 4.844 | 4.655 | 7.594 | 7.406 | 0.438 | 0.047 |
| 1/2 | 0.4975 | 0.5715 | 0.5650 | 1.719 | 1.531 | 5.344 | 5.156 | 8.344 | 8.156 | 0.500 | 0.050 |
| 9/16 | 0.5600 | 0.6420 | 0.6356 | 1.844 | 1.656 | 5.844 | 5.656 | 9.094 | 8.906 | 0.562 | 0.053 |
| 5/8 | 0.6225 | 0.7146 | 0.7080 | 1.969 | 1.781 | 6.344 | 6.156 | 9.844 | 9.656 | 0.625 | 0.055 |
| 3/4 | 0.7470 | 0.8580 | 0.8512 | 2.219 | 2.031 | 7.344 | 7.156 | 11.344 | 11.156 | 0.750 | 0.070 |
| 7/8 | 0.8720 | 1.0020 | 0.9931 | 2.469 | 2.281 | 8.344 | 8.156 | 12.844 | 12.656 | 0.875 | 0.076 |
| 1 | 0.9970 | 1.1470 | 1.1350 | 2.719 | 2.531 | 9.344 | 9.156 | 14.344 | 14.156 | 1.000 | 0.081 |
| 1 1/4 | 1.2430 | 3.250 | 2.750 | 11.500 | 11.000 | 1.250 | 0.092 | ||||
| 1 1/2 | 1.4930 | 3.750 | 3.250 | 13.500 | 13.000 | 1.500 | 0.104 | ||||
| 1 3/4 | 1.743. | 4.250 | 3.750 | 15.500 | 15.000 | 1.750 | 0.115 | ||||
| 2 | 1.9930 | 4.750 | 4.250 | 17.500 | 17.000 | 2.000 | 0.126 | ||||
| 2 1/4 | 2.2430 | 5.250 | 4.750 | 19.500 | 19.000 | 2.250 | 0.137 | ||||
| 2 3/4 | 2.7420 | 6.250 | 5.750 | 23.500 | 23.000 | 2.750 | 0.159 | ||||
| 3 | 2.9920 | 6.750 | 6.250 | 25.500 | 25.000 | 3.000 | 0.171 | ||||
Per ANSI/ASME B18.3
Disclaimer: The dimensions listed are for reference only. Sizes not listed may be available off the shelf or can be manufactured to customer requirements.