A307 Bolts — Strength and Allowable Capacity
The low-strength general-purpose bolt (Grade A). Cheap and widely stocked. Use only where the connection design and specification permit it: handrail, grating clips, light framing, temporary work. Not interchangeable with F3125 structural bolts.
Specified strengths
- Standard: ASTM A307 Grade A
- Tensile strength Fu: 60 ksi
- Nominal tensile stress Fnt: 45 ksi
- Nominal shear stress Fnv: 27 ksi (N and X)
Allowable capacity by diameter
| Diameter | Ab (in²) | A307 tension (kip) | A307 shear (kip) |
|---|---|---|---|
| 1/2" | 0.196 | 4.4 | 2.7 |
| 5/8" | 0.307 | 6.9 | 4.1 |
| 3/4" | 0.442 | 9.9 | 6.0 |
| 7/8" | 0.601 | 13.5 | 8.1 |
| 1" | 0.785 | 17.7 | 10.6 |
| 1-1/8" | 0.994 | 22.4 | 13.4 |
| 1-1/4" | 1.227 | 27.6 | 16.6 |
| 1-1/2" | 1.767 | 39.8 | 23.9 |
Allowable Stress Design (ASD), Ω = 2.00. Bearing-type, snug-tight, one shear plane, threads included (N), nominal shank area. For end-loaded connections with a fastener pattern longer than 38 in., multiply shear by 0.833 per American Institute of Steel Construction (AISC) 360 Table J3.2. Bearing, tearout, block shear, net section, prying and bolt interaction are separate checks. Fu is a material minimum, not an allowable stress.
Where it is used
- Secondary and miscellaneous steel: handrail, grating, ladder clips, kickers.
- Not for pretensioned or slip-critical joints.
- Anchor rods are a different spec: order F1554, not A307.
Identifying it in the field
Head marked "307A" plus the manufacturer's mark (Grade B: "307B"). Do not identify A307 by an absence of markings.
Related
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