1. What is the Metric Bolt Torque Formula?

The metric bolt torque formula calculates the required torque for tightening bolts based on the torque coefficient, bolt diameter, and axial force. This calculation is essential for ensuring proper fastener tension and joint integrity in mechanical applications.

2. How Does the Calculator Work?

The calculator uses the metric bolt torque formula:

Where:

• \( T \) — Torque (N·m)
• \( K \) — Torque coefficient (dimensionless)
• \( D \) — Bolt diameter (mm)
• \( F \) — Axial force (N)

Explanation: The formula calculates the torque required to achieve a specific clamping force in a bolted joint, accounting for friction and other factors through the torque coefficient.

3. Importance of Proper Torque Calculation

Details: Accurate torque calculation is crucial for preventing joint failure, avoiding bolt stretching or breaking, and ensuring proper sealing in pressurized applications.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What is a typical torque coefficient value?
A: For standard unlubricated steel fasteners, K is typically between 0.15-0.25. Lubricated fasteners may have lower values (0.10-0.15).

Q2: How does thread pitch affect torque calculation?
A: Thread pitch is accounted for in the torque coefficient value. Finer threads generally require less torque for the same clamping force.

Q3: Should I use dry or lubricated coefficient values?
A: Use values appropriate for your application. Lubricated values should be used when thread lubricant is applied, as this significantly reduces friction.

Q4: What safety factor should I apply?
A: For critical applications, consult engineering standards. Typically, a safety factor of 1.25-2.0 is applied to the calculated torque.

Q5: Can this calculator be used for inch fasteners?
A: This calculator is specifically designed for metric fasteners. For inch fasteners, different formulas and units are typically used.