M39×4.0 Thread Specifications
Complete dimensions for M39×4.0 coarse pitch thread per ISO 724. Pitch: 4.0mm (6.3 TPI equivalent).
Thread Dimensions
| Designation | M39×4.0 |
| Thread Series | ISO Metric Coarse |
| Pitch | 4.0 mm (6.3 TPI) |
| Major Diameter (d) | 39 mm (1.5354") |
| Pitch Diameter (d₂) | 36.402 mm (1.4331") |
| Minor Diameter — External (d₁) | 34.0924 mm (1.3422") |
| Minor Diameter — Internal (D₁) | 34.67 mm (1.365") |
| Thread Depth | 2.1651 mm |
| Tensile Stress Area | 975.75 mm² |
| Fundamental Triangle Height (H) | 3.4641 mm |
Tap Drill Size
Recommended tap drill: 35.0 mm
Calculated minor diameter (D₁): 34.67 mm. Closest standard metric drill: 35.0 mm.
Closest inch drill: 1-23/64" (1.3594" / 34.53 mm)
Proof Loads by Property Class
| Class | Proof Stress (MPa) | Tensile Strength (MPa) | Proof Load (kN) | Tensile Load (kN) |
|---|---|---|---|---|
| 4.6 | 225 | 400 | 219.5 | 390.3 |
| 4.8 | 310 | 420 | 302.5 | 409.8 |
| 5.8 | 380 | 520 | 370.8 | 507.4 |
| 8.8 | 580 | 800 | 565.9 | 780.6 |
| 9.8 | 650 | 900 | 634.2 | 878.2 |
| 10.9 | 830 | 1040 | 809.9 | 1014.8 |
| 12.9 | 970 | 1220 | 946.5 | 1190.4 |
Proof load = stress area × proof stress. Per ISO 898-1.
Related Thread Sizes
Common Applications
- Structural steel
- Bridge construction
- Heavy industrial equipment
- Foundation bolts
How M39×4.0 Dimensions Are Calculated
All dimensions on this page are calculated from ISO 724 formulas using the nominal diameter (39 mm) and pitch (4.0 mm):
- Fundamental triangle height: H = (√3/2) × P = 3.4641 mm
- Pitch diameter: d₂ = d − 0.6495 × P = 36.402 mm
- Minor diameter (external): d₁ = d − 1.2269 × P = 34.0924 mm
- Minor diameter (internal): D₁ = d − 1.0825 × P = 34.67 mm
- Thread depth: 5H/8 = 2.1651 mm
- Tensile stress area: Aₛ = (π/4) × ((d₂ + d₃)/2)² = 975.75 mm²