M4×0.5 Thread Specifications
Complete dimensions for M4×0.5 fine pitch thread per ISO 724. Pitch: 0.5mm (50.8 TPI equivalent).
Thread Dimensions
| Designation | M4×0.5 |
| Thread Series | ISO Metric Fine |
| Pitch | 0.5 mm (50.8 TPI) |
| Major Diameter (d) | 4 mm (0.1575") |
| Pitch Diameter (d₂) | 3.6753 mm (0.1447") |
| Minor Diameter — External (d₁) | 3.3865 mm (0.1333") |
| Minor Diameter — Internal (D₁) | 3.4588 mm (0.1362") |
| Thread Depth | 0.2706 mm |
| Tensile Stress Area | 9.59 mm² |
| Fundamental Triangle Height (H) | 0.433 mm |
Tap Drill Size
Recommended tap drill: 3.5 mm
Calculated minor diameter (D₁): 3.46 mm. Closest standard metric drill: 3.5 mm.
Closest inch drill: #29 (0.136" / 3.45 mm)
Proof Loads by Property Class
| Class | Proof Stress (MPa) | Tensile Strength (MPa) | Proof Load (kN) | Tensile Load (kN) |
|---|---|---|---|---|
| 4.6 | 225 | 400 | 2.2 | 3.8 |
| 4.8 | 310 | 420 | 3.0 | 4.0 |
| 5.8 | 380 | 520 | 3.6 | 5.0 |
| 8.8 | 580 | 800 | 5.6 | 7.7 |
| 9.8 | 650 | 900 | 6.2 | 8.6 |
| 10.9 | 830 | 1040 | 8.0 | 10.0 |
| 12.9 | 970 | 1220 | 9.3 | 11.7 |
Proof load = stress area × proof stress. Per ISO 898-1.
Related Thread Sizes
Common Applications
- Precision instruments
- Optical equipment
- Aerospace fasteners
- Vibration-resistant assemblies
How M4×0.5 Dimensions Are Calculated
All dimensions on this page are calculated from ISO 724 formulas using the nominal diameter (4 mm) and pitch (0.5 mm):
- Fundamental triangle height: H = (√3/2) × P = 0.433 mm
- Pitch diameter: d₂ = d − 0.6495 × P = 3.6753 mm
- Minor diameter (external): d₁ = d − 1.2269 × P = 3.3865 mm
- Minor diameter (internal): D₁ = d − 1.0825 × P = 3.4588 mm
- Thread depth: 5H/8 = 0.2706 mm
- Tensile stress area: Aₛ = (π/4) × ((d₂ + d₃)/2)² = 9.59 mm²