Bolt Torque to Clamp Load

Short-form torque T = K * D * F with grade proof loads.

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Formula and source

T = K × D × F where T is torque (ft-lb), K is the nut factor, D is bolt diameter, F is desired clamp load (= proof load × torque-tension factor). Proof loads per ASTM / SAE bolt-grade specifications.

ASTM A325 / A490 / SAE J429 by name.

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