Proof Load
Definition
The maximum load a fastener can withstand without permanent deformation. It is typically 85-95% of yield strength and represents the practical upper limit for bolt preload.
Practical Note
Proof load = Proof Strength × Stress Area. Never exceed proof load during tightening as the bolt will yield and lose preload over time.
Related Calculators
🔧Bolt Torque Calculator
Calculate bolt torque, preload force, and clamping force for threaded fasteners. Supports metric and imperial threads.
🔧Bolt Size Chart
Interactive bolt size reference. Look up head dimensions, thread specifications, recommended hole sizes, and matching nut dimensions for hex bolts in SAE and metric standards.