Engineering Data Sheets
Fastener Data Sheets& CAD
Browse ISO, DIN, ASTM and ASME fastener standards with dimensional specifications, CAD blueprints, drilling & clearance data, chemical composition and mechanical properties.
Reference: ASME B18.2.1 / ASTM A325
Fastener Catalog & Standard Specification
Active: ASME B18.2.1 / ASTM A325 (Heavy Hex Structural Bolt)
Select a fastener below to view its data sheet
ASME B18.2.1 / ASTM A325ASTM STANDARDPartial ThreadUNC
Heavy Hex Structural Bolts (Imperial / ASTM)
Imperial heavy hex bolts featuring a larger width across flats (A/F) than standard hex bolts, engineered for steel-to-steel structural connections.
CAD Schematic
Nominal blueprint for 7/8"
Engineering Schematic / CAD Dimension InspectorModel: 7/8" × 50mm
Nominal Thread (d)7/8" P=9 TPImm
Wrench / Allen (s)36.5mm e=42
Tap Drill DiameterØ 19.5 mm
Tensile Stress Area (Aₛ)298 mm²
Manufacturing & Drilling Engineering Notes
- • Heavy hex width across flats equals: 1.5 × Nominal Diameter + 1/8".
- • Requires ASTM F436 hardened structural washers to prevent bolt relaxation.
Size Specification Inspector
7/8"Select diameter & order quantity
Select Nominal Thread Diameter
Thread Pitch9 TPI mm
Wrench (A/F Spanner s)36.5 mm
Recommended Tap DrillØ 19.5 mm
Clearance Hole (H13)Ø 23.8 mm
Tensile Stress Area (Aₛ)298 mm²
Single unit weight (steel): 0.1736 kg
Chemical Composition & Metallurgy
Elemental mass percentages, grain structure & mechanical properties
Elemental Composition (Mass %)
CCarbon0.25 - 0.55%
MnManganese0.60 - 1.20%
PPhosphorus0.025% max
SSulfur0.025% max
SiSilicon0.15 - 0.35%
CrChromium0.20 - 0.50% (Optional)
BBoron0.0008 - 0.005% (Boron-treated)
FeIronBalance (~97.5%)
Mechanical Strength & Heat Treatment
Metallurgical Notes
- • Quenched and tempered at min 425°C to achieve fine tempered martensite microstructure.
- • Meets ISO 898-1 / ASTM F568M Class 8.8 specifications.
- • Boron-alloyed steels must contain min 0.0008% active Boron for hardenability.
Dimensional Specification
Thread / Pitch / Across Flats / Corners / Height / Drill / Clearance / Stress Area (mm)
| Thread (d) | Pitch | A/F (s) | Corners (e) | Height | Tap Drill | Clear H13 | Stress Area | |
|---|---|---|---|---|---|---|---|---|
| 1/2" | 13 TPI | 22.2 | 25.4 | 8.3 | 10.8 | 14.3 | 91.5 | |
| 5/8" | 11 TPI | 27 | 31 | 10.3 | 13.6 | 17.5 | 146 | |
| 3/4" | 10 TPI | 31.8 | 36.5 | 12.3 | 16.5 | 20.6 | 216 | |
| 7/8" | 9 TPI | 36.5 | 42 | 14.3 | 19.5 | 23.8 | 298 | |
| 1" | 8 TPI | 41.3 | 47.5 | 16 | 22.2 | 27 | 391 | |
| 1-1/8" | 7 TPI (or 8-UN) | 46 | 53 | 18 | 25 | 30.2 | 492 | |
| 1-1/4" | 7 TPI (or 8-UN) | 50.8 | 58.5 | 20 | 28.2 | 33.3 | 625 | |
| 1-3/8" | 6 TPI (or 8-UN) | 55.6 | 64 | 22 | 30.8 | 36.5 | 745 | |
| 1-1/2" | 6 TPI (or 8-UN) | 60.3 | 69.5 | 24 | 34 | 39.7 | 908 |