Comprehensive fastener torque specifications, bolt dimensions, and engineering reference data for mechanical design.
Comprehensive reference for bolt sizes, torque specifications, and fastener properties
Grade 5 bolts, dry conditions
| Size | Coarse Thread | Fine Thread |
|---|---|---|
| 1/4"-20 | 8 | 9 |
| 5/16"-18 | 17 | 19 |
| 3/8"-16 | 31 | 35 |
| 7/16"-14 | 49 | 55 |
| 1/2"-13 | 75 | 85 |
| 9/16"-12 | 109 | 123 |
| 5/8"-11 | 150 | 169 |
| 3/4"-10 | 270 | 304 |
| 7/8"-9 | 395 | 446 |
| 1"-8 | 590 | 665 |
Grade 8.8 bolts, dry conditions
| Size | Coarse Thread | Fine Thread |
|---|---|---|
| M6×1.0 | 10 | 12 |
| M8×1.25 | 25 | 28 |
| M10×1.5 | 50 | 57 |
| M12×1.75 | 90 | 102 |
| M14×2.0 | 140 | 158 |
| M16×2.0 | 225 | 255 |
| M18×2.5 | 310 | 350 |
| M20×2.5 | 435 | 490 |
| M22×2.5 | 580 | 650 |
| M24×3.0 | 750 | 850 |
ANSI/ASME B18.3.1M standard
| Size | Head Diameter | Head Height | Hex Key Size |
|---|---|---|---|
| 1/4"-20 | 0.375" | 0.250" | 3/16" |
| 5/16"-18 | 0.469" | 0.313" | 1/4" |
| 3/8"-16 | 0.563" | 0.375" | 5/16" |
| 7/16"-14 | 0.656" | 0.438" | 3/8" |
| 1/2"-13 | 0.750" | 0.500" | 7/16" |
| 5/8"-11 | 0.938" | 0.625" | 9/16" |
| 3/4"-10 | 1.125" | 0.750" | 5/8" |
| 7/8"-9 | 1.313" | 0.875" | 3/4" |
| 1"-8 | 1.500" | 1.000" | 7/8" |
Heavy hex nuts, ANSI B18.2.2
| Size | Width Across Flats | Width Across Corners | Thickness |
|---|---|---|---|
| 1/4"-20 | 0.438" | 0.505" | 0.226" |
| 5/16"-18 | 0.563" | 0.650" | 0.289" |
| 3/8"-16 | 0.625" | 0.722" | 0.352" |
| 7/16"-14 | 0.750" | 0.866" | 0.446" |
| 1/2"-13 | 0.875" | 1.010" | 0.508" |
| 5/8"-11 | 1.125" | 1.299" | 0.633" |
| 3/4"-10 | 1.313" | 1.516" | 0.727" |
| 7/8"-9 | 1.500" | 1.732" | 0.852" |
| 1"-8 | 1.688" | 1.949" | 0.946" |
UNC (Coarse) and UNF (Fine) threads
| Size | UNC (Coarse) | UNF (Fine) | Pitch (inches) |
|---|---|---|---|
| #4 | 40 | 48 | 0.025 / 0.021 |
| #6 | 32 | 40 | 0.031 / 0.025 |
| #8 | 32 | 36 | 0.031 / 0.028 |
| #10 | 24 | 32 | 0.042 / 0.031 |
| #12 | 24 | 28 | 0.042 / 0.036 |
| 1/4" | 20 | 28 | 0.050 / 0.036 |
| 5/16" | 18 | 24 | 0.056 / 0.042 |
| 3/8" | 16 | 24 | 0.063 / 0.042 |
| 7/16" | 14 | 20 | 0.071 / 0.050 |
| 1/2" | 13 | 20 | 0.077 / 0.050 |
ISO metric coarse and fine threads
| Size | Coarse Pitch | Fine Pitch | Extra Fine |
|---|---|---|---|
| M3 | 0.5 | - | - |
| M4 | 0.7 | 0.5 | - |
| M5 | 0.8 | 0.5 | - |
| M6 | 1.0 | 0.75 | 0.5 |
| M8 | 1.25 | 1.0 | 0.75 |
| M10 | 1.5 | 1.25 | 1.0 |
| M12 | 1.75 | 1.5 | 1.25 |
| M14 | 2.0 | 1.5 | 1.25 |
| M16 | 2.0 | 1.5 | 1.0 |
| M20 | 2.5 | 2.0 | 1.5 |
Common fastener steel grades
| Grade | Tensile Strength (psi) | Yield Strength (psi) | Material |
|---|---|---|---|
| Grade 2 | 74,000 | 57,000 | Low/Medium Carbon Steel |
| Grade 5 | 120,000 | 92,000 | Medium Carbon Steel |
| Grade 8 | 150,000 | 130,000 | Medium Carbon Alloy Steel |
| A325 | 120,000 | 92,000 | Structural Bolts |
| A490 | 150,000 | 130,000 | High Strength Structural |
| 316 SS | 80,000 | 30,000 | Stainless Steel |
ISO metric fastener grades
| Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Material |
|---|---|---|---|
| 4.6 | 400 | 240 | Low Carbon Steel |
| 5.8 | 500 | 400 | Medium Carbon Steel |
| 8.8 | 800 | 640 | Medium Carbon Steel |
| 10.9 | 1000 | 900 | Alloy Steel |
| 12.9 | 1200 | 1080 | Alloy Steel |
| A2-70 | 700 | 450 | Stainless Steel |