1. What is Bolt Torque?

Bolt torque is the rotational force applied to tighten a fastener. Proper torque ensures adequate clamping force without damaging the bolt or the materials being fastened.

2. How Does the Calculator Work?

The calculator uses the bolt torque equation:

Where:

• \( \tau \) — Torque (N·m)
• \( K \) — Torque coefficient (dimensionless)
• \( F \) — Clamping force (N)
• \( d \) — Bolt diameter (m)

Explanation: The torque coefficient accounts for friction and other factors that affect how much of the applied torque converts to clamping force.

3. Importance of Torque Calculation

Details: Proper torque is critical for joint integrity. Under-torquing can lead to loosening, while over-torquing can damage threads or stretch bolts.

4. Using the Calculator

Tips: Enter the torque coefficient (typically 0.15-0.25 for dry, unlubricated bolts), desired clamping force in newtons, and bolt diameter in meters.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical torque coefficient value?
A: For dry, unlubricated bolts, K is typically 0.15-0.25. Lubricated bolts may have K values as low as 0.10.

Q2: How does bolt material affect torque?
A: Different materials have different friction coefficients and strength limits, affecting both K values and maximum safe torque.

Q3: Should I use the same torque for all bolts in an assembly?
A: Generally yes, unless specified otherwise. Always follow manufacturer recommendations when available.

Q4: How accurate is this calculation?
A: This provides an estimate. Actual torque needed may vary due to surface finish, lubrication, and other factors.

Q5: What about bolt preload?
A: For critical applications, consider calculating preload directly as torque is only an indirect measure of preload.