Clamping Force Formula:
Where:
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The bolt clamping force is the compressive force that a bolt exerts on the joint when tightened. It's crucial for maintaining joint integrity and preventing loosening under load.
The calculator uses the clamping force formula:
Where:
Explanation: The formula shows that clamping force is directly proportional to torque and inversely proportional to both the nut factor and bolt diameter.
Details: Proper clamping force ensures joint integrity, prevents bolt loosening from vibration, and maintains proper gasket compression in sealed joints.
Tips: Enter torque in ft-lb, nut factor (default is 0.2 for dry, unlubricated bolts), and bolt diameter in inches. All values must be positive numbers.
Q1: What is a typical nut factor (K) value?
A: For dry, unlubricated bolts: ~0.2. For lubricated bolts: ~0.15-0.18. Highly lubricated: as low as 0.1.
Q2: Why does bolt diameter affect clamping force?
A: Larger diameter bolts distribute the torque over a larger radius, resulting in less axial force for the same torque.
Q3: How accurate is this calculation?
A: It provides a good estimate but actual values vary due to friction, lubrication, surface finish, and bolt condition.
Q4: What affects the nut factor?
A: Thread condition, lubrication, surface finish, and washers all influence the nut factor.
Q5: Should I use this for critical applications?
A: For critical joints, consult engineering specifications or perform actual tension measurements.