1. What Is The Torque Tightening Formula?

The torque tightening formula T = K × F × D calculates the tightening torque for screws and bolts, where T is the torque, K is the nut factor (coefficient of friction), F is the axial force, and D is the nominal diameter.

2. How Does The Calculator Work?

The calculator uses the torque equation:

Where:

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

Explanation: The equation calculates the rotational force needed to achieve proper bolt tension while accounting for friction losses.

3. Importance Of Proper Torque Calculation

Details: Accurate torque calculation is crucial for ensuring proper joint clamping force, preventing bolt failure, avoiding loosening under vibration, and maintaining structural integrity.

4. Using The Calculator

Tips: Enter the coefficient K (typically 0.15-0.25 for lubricated bolts, 0.20-0.30 for dry), axial force in Newtons, and diameter in meters. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical K value for bolts?
A: For standard steel bolts, K is typically between 0.15-0.25 for lubricated conditions and 0.20-0.30 for dry conditions.

Q2: How does lubrication affect torque calculation?
A: Lubrication reduces friction, allowing more of the applied torque to convert to bolt tension, requiring less torque for the same clamping force.

Q3: Why is proper torque important?
A: Under-torquing can lead to joint separation and bolt loosening, while over-torquing can cause bolt stretching, thread damage, or fracture.

Q4: Does bolt material affect the calculation?
A: Yes, different materials have different friction coefficients and strength properties that affect the K value and maximum allowable torque.

Q5: When should torque be measured directly?
A: For critical applications, direct torque measurement with a calibrated torque wrench is recommended rather than relying solely on calculations.