Workholding · Released

Clamping Force Estimator

Estimate clamping force from screw torque or hydraulic cylinder pressure. Knowing your actual clamping force helps prevent part movement, fixture deflection, and part deformation.

Method

Applied torque (N·m)

Thread pitch

Friction efficiency μ

Estimated clamping force

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Safety check

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Formulas

Screw clamp (approximate): F ≈ (2000 × T) / d × η, where T = torque (N·m), d = bolt diameter (mm), η = friction efficiency factor. This is a shop-floor approximation; actual preload depends on thread condition, washer friction, and bolt grade.

Hydraulic cylinder: F = P × A, where P = pressure (N/mm² = bar × 0.1), A = piston area (mm²).

Rule of thumb: clamping force should be at least 3–5× the maximum cutting force. If the part can flex, spread the force with a larger contact pad. Never clamp on thin walls — support from below.