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The nominal bolt diameter calculation determines the required bolt size based on wrench torque and pre-load requirements. This is essential for ensuring proper bolt tension and joint integrity in mechanical assemblies.
The calculator uses the formula:
Where:
Explanation: The formula calculates the nominal bolt diameter required to achieve a specific pre-load with a given wrench torque, using a standard coefficient of 0.2 for friction.
Details: Proper bolt sizing is crucial for structural integrity, safety, and performance of mechanical joints. Undersized bolts may fail under load, while oversized bolts can damage components and increase costs.
Tips: Enter wrench torque in Newton-meters and pre-load in Newtons. Both values must be positive numbers. The calculator will determine the required nominal bolt diameter in meters.
Q1: What is the significance of the 0.2 coefficient?
A: The 0.2 coefficient represents the typical friction factor between bolt threads and nut, accounting for both thread friction and bearing surface friction.
Q2: How accurate is this calculation?
A: This provides a good estimate for standard applications, but actual results may vary based on specific materials, lubrication, and surface conditions.
Q3: Can this formula be used for metric and imperial bolts?
A: Yes, the formula is dimensionally consistent. Just ensure all units are consistent (N·m for torque, N for load, m for diameter).
Q4: What factors affect the friction coefficient?
A: Surface finish, lubrication, material combination, and thread quality all influence the actual friction coefficient.
Q5: Should safety factors be applied to the result?
A: Yes, engineering applications typically apply appropriate safety factors based on the criticality of the joint and loading conditions.