1. What is the Bolt Torque Formula?

The bolt torque formula (T = K × F × D) calculates the torque required to achieve a specific axial load (clamp force) in a bolted joint. This is essential for proper fastener tensioning in mechanical assemblies.

2. How Does the Calculator Work?

The calculator uses the bolt torque formula:

Where:

• \( T \) — Torque (Nm)
• \( K \) — Torque coefficient (dimensionless)
• \( F \) — Axial force (N)
• \( D \) — Nominal diameter (m)

Explanation: The formula relates the applied torque to the resulting clamp force, accounting for friction and geometric factors through the torque coefficient.

3. Importance of Bolt Torque Calculation

Details: Proper bolt torque ensures joint integrity, prevents loosening, avoids over-tightening that can damage threads, and maintains consistent clamping force in mechanical assemblies.

4. Using the Calculator

Tips: Enter the torque coefficient (typically 0.15-0.25 for standard bolts), desired axial force in Newtons, and nominal diameter in meters. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical torque coefficient value?
A: For standard steel bolts with lubrication, K is typically 0.15-0.25. Dry or poorly lubricated bolts may have higher coefficients up to 0.3-0.4.

Q2: Why is proper bolt torque important?
A: Correct torque ensures adequate clamping force for joint integrity while preventing bolt failure, thread stripping, or damage to connected components.

Q3: How does lubrication affect torque requirements?
A: Lubrication reduces friction, allowing more of the applied torque to convert to clamp force. This means less torque is needed to achieve the same clamping force.

Q4: What factors influence the torque coefficient?
A: Surface finish, lubrication, thread pitch, material properties, and washers all affect the torque coefficient value.

Q5: Should torque be measured or calculated for critical applications?
A: For critical applications, both calculation and direct measurement (using torque wrenches or tension measurement devices) are recommended to ensure accuracy.