1. What is the Torque Equation?

The torque equation (T = K × D × P) calculates the torque required to achieve proper bolt preload. It's essential for ensuring structural integrity in steel bolted connections.

2. How Does the Calculator Work?

The calculator uses the torque equation:

Where:

• \( T \) — Torque (lb-ft)
• \( K \) — Torque coefficient (unitless)
• \( D \) — Bolt diameter (inches)
• \( P \) — Bolt preload (lbs)

Explanation: The equation accounts for friction and geometric factors in bolted joints to determine proper tightening torque.

3. Importance of Torque Calculation

Details: Proper torque ensures adequate clamping force without overstressing the bolt, preventing joint failure or bolt breakage.

4. Using the Calculator

Tips: Enter the torque coefficient (typically 0.2 for steel bolts), bolt diameter in inches, and desired preload in pounds. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical K value for steel bolts?
A: For steel bolts, K typically ranges from 0.15 to 0.25, with 0.2 being a common default value.

Q2: How do I determine preload (P)?
A: Preload is typically 60-75% of bolt proof load, which depends on bolt grade and size.

Q3: Does lubrication affect torque calculations?
A: Yes, lubrication reduces friction and requires a lower K value. Always use K values appropriate for your specific conditions.

Q4: What about metric bolts?
A: The same equation applies, but use consistent units (N·m for torque, mm for diameter, and N for preload).

Q5: How accurate is this calculation?
A: While useful for estimation, actual torque requirements can vary ±25% due to friction variations. Critical applications may require torque testing.