Torque Accuracy & Specifications for Titanium Fasteners
Understanding proper torque is critical to component longevity and safety in high-performance applications like motorsports. While screw threads may appear simple, torque application is influenced by many factors—including surface finish, materials, and lubrication.
⚙️ The Truth About Torque Accuracy
Despite common assumptions, tightening fasteners isn't an exact science. Various methods deliver significantly different levels of preload accuracy.
🔬 Torque Method Accuracy (From Machinery’s Handbook, 25th Edition, p. 1404)
| Method | Estimated Accuracy |
|---|---|
| By Feel | ±35% |
| Standard Torque Wrench | ±25% |
| Turn-of-Nut Method | ±15% |
| Preload Washers | ±10% |
| Bolt Elongation | ±3% |
| Strain Gauges (Elongation) | ±1% |
💡 Takeaway: Torque values should be viewed as guidelines, not absolutes—especially when no lubrication or preload monitoring is used.
🧰 Titanium Fasteners: Best Practices
When tightening titanium bolts, use the equipment manufacturer’s specs when available. If those aren't provided, refer to the chart below. We strongly recommend using anti-seize or moly paste on the threads to reduce friction and prevent galling.
⚠️ Why Correct Torque Matters
- Undertorque: Causes loosening, vibration, uneven load distribution, and fatigue failures.
- Overtorque: Risks stripping threads or snapping the fastener—especially critical in titanium, which lacks ductility.
🔩 Torque Limits for Titanium Bolts – Inch-Pound Values
For bolts in shear, reduce torque values by 30–40%.
Lubricated vs. Non-Lubricated
| Bolt Size | Non-Lubricated (Min–Max) | Lubricated (Min–Max) |
|---|---|---|
| 5/16-18 | 80 – 90 in-lbs | 72 – 81 in-lbs |
| 5/16-24 | 120 – 145 in-lbs | 108 – 130 in-lbs |
| 3/8-16 | 160 – 185 in-lbs | 144 – 148 in-lbs |
| 3/8-24 | 200 – 250 in-lbs | 180 – 225 in-lbs |
| 7/16-14 | 235 – 255 in-lbs | 211 – 229 in-lbs |
| 7/16-20 | 520 – 630 in-lbs | 468 – 567 in-lbs |
| ½-13 | 400 – 480 in-lbs | 360 – 432 in-lbs |
| ½-20 | 770 – 950 in-lbs | 693 – 855 in-lbs |
🛑 Never exceed max torque—especially on titanium or aluminum threads.
✅ Summary
- Always lube threads unless dry torque is explicitly required.
- Use torque specs as a starting point, not gospel.
- When available, measure bolt stretch or preload rather than relying solely on torque wrenches.
- In critical areas (suspension, brakes, drivetrain), consider adding torque seal paint or witness marks to monitor loosening.