M2.5×0.45 Thread Specifications
Complete dimensions for M2.5×0.45 coarse pitch thread per ISO 724. Pitch: 0.45mm (56.4 TPI equivalent).
Thread Dimensions
| Designation | M2.5×0.45 |
| Thread Series | ISO Metric Coarse |
| Pitch | 0.45 mm (56.4 TPI) |
| Major Diameter (d) | 2.5 mm (0.0984") |
| Pitch Diameter (d₂) | 2.2077 mm (0.0869") |
| Minor Diameter — External (d₁) | 1.9479 mm (0.0767") |
| Minor Diameter — Internal (D₁) | 2.0129 mm (0.0792") |
| Thread Depth | 0.2436 mm |
| Tensile Stress Area | 3.29 mm² |
| Fundamental Triangle Height (H) | 0.3897 mm |
Tap Drill Size
Recommended tap drill: 2.0 mm
Calculated minor diameter (D₁): 2.01 mm. Closest standard metric drill: 2.0 mm.
Closest inch drill: #47 (0.0785" / 1.99 mm)
Proof Loads by Property Class
| Class | Proof Stress (MPa) | Tensile Strength (MPa) | Proof Load (kN) | Tensile Load (kN) |
|---|---|---|---|---|
| 4.6 | 225 | 400 | 0.7 | 1.3 |
| 4.8 | 310 | 420 | 1.0 | 1.4 |
| 5.8 | 380 | 520 | 1.3 | 1.7 |
| 8.8 | 580 | 800 | 1.9 | 2.6 |
| 9.8 | 650 | 900 | 2.1 | 3.0 |
| 10.9 | 830 | 1040 | 2.7 | 3.4 |
| 12.9 | 970 | 1220 | 3.2 | 4.0 |
Proof load = stress area × proof stress. Per ISO 898-1.
Common Applications
- Electronics
- Instrument screws
- Watch mechanisms
- Small fasteners
How M2.5×0.45 Dimensions Are Calculated
All dimensions on this page are calculated from ISO 724 formulas using the nominal diameter (2.5 mm) and pitch (0.45 mm):
- Fundamental triangle height: H = (√3/2) × P = 0.3897 mm
- Pitch diameter: d₂ = d − 0.6495 × P = 2.2077 mm
- Minor diameter (external): d₁ = d − 1.2269 × P = 1.9479 mm
- Minor diameter (internal): D₁ = d − 1.0825 × P = 2.0129 mm
- Thread depth: 5H/8 = 0.2436 mm
- Tensile stress area: Aₛ = (π/4) × ((d₂ + d₃)/2)² = 3.29 mm²