‡Length of a machine bolt is measured from the underhead bearing surface to the extreme end of the bolt.
| Hex Bolt Dimensions (ANSI B18.2.1-1996) | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Nominal Click on Size to Shop Products |
Body Diameter (E) |
Width |
Width Across Corners (G) | Head Height (H) |
Radius of Fillet (R) |
Thread |
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| Max | Min | Basic | Max | Min | Max | Min | Basic | Max | Min | Max | Min | Basic (6 in. and shorter) | Basic (Over 6 in.) | ||
| 1/4 (0.2500) | 0.260 | 0.237 | 7/16 | 0.438 | 0.425 | 0.505 | 0.484 | 11/64 | 0.188 | 0.150 | 0.03 | 0.01 | 0.750 | 1.000 | |
| 5/16 (0.3125) | 0.324 | 0.298 | 1/2 | 0.500 | 0.484 | 0.577 | 0.552 | 7/32 | 0.235 | 0.195 | 0.03 | 0.01 | 0.875 | 1.125 | |
| 3/8 (0.3750) | 0.388 | 0.360 | 9/16 | 0.562 | 0.544 | 0.650 | 0.620 | 1/4 | 0.268 | 0.226 | 0.03 | 0.01 | 1.000 | 1.250 | |
| 1/2 (0.5000) | 0.515 | 0.482 | 3/4 | 0.750 | 0.725 | 0.866 | 0.826 | 11/32 | 0.364 | 0.302 | 0.03 | 0.01 | 1.250 | 1.500 | |
| 5/8 (0.6250) | 0.642 | 0.605 | 15/16 | 0.938 | 0.906 | 1.083 | 1.033 | 27/64 | 0.444 | 0.378 | 0.06 | 0.02 | 1.500 | 1.750 | |
| 3/4 (0.7500) | 0.768 | 0.729 | 1-1/8 | 1.125 | 1.088 | 1.299 | 1.240 | 1/2 | 0.524 | 0.455 | 0.06 | 0.02 | 1.750 | 2.000 | |
| 7/8 (0.8750) | 0.895 | 0.852 | 1-5/16 | 1.312 | 1.269 | 1.516 | 1.447 | 37/64 | 0.604 | 0.531 | 0.06 | 0.02 | 2.000 | 2.250 | |
| 1 (1.0000) | 1.022 | 0.976 | 1-1/2 | 1.500 | 1.450 | 1.732 | 1.653 | 43/64 | 0.700 | 0.591 | 0.09 | 0.03 | 2.250 | 2.500 | |
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Up to 1in., incl. |
Over 1 in. to |
Over 2-1/2 in. to |
Over 4 in. to 6 in., incl. |
Longer than 6 in. |
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| 1/4 to 3/8 | ±0.02, -0.03 | ±0.02, -0.04 | ±0.04, -0.06 | ±0.06, -0.10 |
±0.10, -0.18 |
|
|
7/16 and 1/2 |
±0.02, -0.03 |
±0.02, -0.06 |
±0.06, -0.08 |
±0.08, -0.10 |
±0.12, -0.18 |
|
| 9/16 to 3/4 |
±0.02, -0.03 | ±0.02, -0.08 | ±0.08, -0.10 | ±0.10, -0.10 |
±0.14, -0.18 |
|
| 7/8 and 1 | ... | ±0.02, -0.10 | ±0.10, -0.14 | ±0.12, -0.16 |
±0.16, -0.20 |
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Description |
A mechanical device of low or medium carbon steel, externally threaded, 1/4 inch in diameter or wider, with a hex head trimmed and a galvanized hot dip coating. A hex bolt like a hex cap screw, does not have a washer face on its bearing surface nor a machined rim. The tolerances of the body are not as similar as a cap screw. |
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Application/Advantages |
Designed for use in highly corrosive environments (i.e. coastal areas and highly contaminated atmospheres). Can be inserted into an oversized hole and assembled with a nut. | |||||
| Material |
Device bolts are made of steel that complies with the following requirements for chemical composition: Phosphorus: maximum 0.06%; Sulfur: maximum 0.15%. |
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Hardness |
Bolts of a length < 3X nominal diameter: Rockwell B69 - B100. |
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| Tensile Strength | 60,000 psi. minimum. | |||||
| Elongation* | 18% minimum (all diameters) | |||||
| Plating | See Appendix-A for more plating information. | |||||
*These properties are tested only on machined specimens when the testing machine cannot provide for full testing of the parts.
**Product standards require the manufacturer’s head marking to appear on the top of all bolts 1/4” diameter and larger. “X” represents one location such a marking may appear.
Additional Resources
