1. What is the Screw Torque Equation?

The screw torque equation calculates the torque required to achieve a specific clamping force in bolted joints. It's a fundamental equation in mechanical engineering and fastener design.

2. How Does the Calculator Work?

The calculator uses the screw torque equation:

Where:

• \( T \) — Torque (Nm)
• \( K \) — Torque coefficient (dimensionless)
• \( F \) — Force (N)
• \( D \) — Diameter (m)

Explanation: The equation calculates the torque required based on the desired clamping force, bolt diameter, and a torque coefficient that accounts for friction and other factors.

3. Importance of Torque Calculation

Details: Accurate torque calculation is crucial for proper bolt tightening, preventing joint failure, ensuring structural integrity, and maintaining safety in mechanical assemblies.

4. Using the Calculator

Tips: Enter torque coefficient (typically 0.2 for dry steel), desired clamping force in Newtons, and bolt diameter in meters. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical torque coefficient value?
A: For dry steel fasteners, K is typically around 0.2. For lubricated fasteners, it can be as low as 0.15.

Q2: Why is accurate torque important?
A: Under-torquing can lead to joint loosening, while over-torquing can cause bolt stretching or breakage.

Q3: Does thread pitch affect torque calculation?
A: Thread pitch is accounted for in the torque coefficient value (K), which includes both thread and bearing surface friction effects.

Q4: Can this equation be used for all fastener types?
A: This is a simplified equation suitable for most standard fasteners. Special fasteners may require more complex calculations.

Q5: How does lubrication affect torque values?
A: Lubrication reduces friction, which lowers the torque coefficient and requires less torque to achieve the same clamping force.