M39×3.0 Thread Specifications
Complete dimensions for M39×3.0 fine pitch thread per ISO 724. Pitch: 3.0mm (8.5 TPI equivalent).
Thread Dimensions
| Designation | M39×3.0 |
| Thread Series | ISO Metric Fine |
| Pitch | 3.0 mm (8.5 TPI) |
| Major Diameter (d) | 39 mm (1.5354") |
| Pitch Diameter (d₂) | 37.0515 mm (1.4587") |
| Minor Diameter — External (d₁) | 35.3193 mm (1.3905") |
| Minor Diameter — Internal (D₁) | 35.7525 mm (1.4076") |
| Thread Depth | 1.6238 mm |
| Tensile Stress Area | 1016.12 mm² |
| Fundamental Triangle Height (H) | 2.5981 mm |
Tap Drill Size
Recommended tap drill: 36.0 mm
Calculated minor diameter (D₁): 35.75 mm. Closest standard metric drill: 36.0 mm.
Closest inch drill: 1/1" (1.0" / 25.4 mm)
Proof Loads by Property Class
| Class | Proof Stress (MPa) | Tensile Strength (MPa) | Proof Load (kN) | Tensile Load (kN) |
|---|---|---|---|---|
| 4.6 | 225 | 400 | 228.6 | 406.4 |
| 4.8 | 310 | 420 | 315.0 | 426.8 |
| 5.8 | 380 | 520 | 386.1 | 528.4 |
| 8.8 | 580 | 800 | 589.3 | 812.9 |
| 9.8 | 650 | 900 | 660.5 | 914.5 |
| 10.9 | 830 | 1040 | 843.4 | 1056.8 |
| 12.9 | 970 | 1220 | 985.6 | 1239.7 |
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 M39×3.0 Dimensions Are Calculated
All dimensions on this page are calculated from ISO 724 formulas using the nominal diameter (39 mm) and pitch (3.0 mm):
- Fundamental triangle height: H = (√3/2) × P = 2.5981 mm
- Pitch diameter: d₂ = d − 0.6495 × P = 37.0515 mm
- Minor diameter (external): d₁ = d − 1.2269 × P = 35.3193 mm
- Minor diameter (internal): D₁ = d − 1.0825 × P = 35.7525 mm
- Thread depth: 5H/8 = 1.6238 mm
- Tensile stress area: Aₛ = (π/4) × ((d₂ + d₃)/2)² = 1016.12 mm²