Bolt Connection Calculators

Tightening Force of the Two-bolt Clamp Under Axial Load

In this calculation, a clamp with two bolts, attached to a bar is considered. The bar is under the action of axial force P and kept from slipping by the frictional force generated by the torque of the fastening bolt. As a result of calculations, the tightening force F ensuring the operability of the connection is determined.

For the calculation, the friction coefficient of the contacted surfaces μ should be specified.

The tightening torque of the thread can be calculated here.

Tightening Force Calculation of the Two-bolt Clamp under Axial Load

Calculation of Tightening Force of the Two-bolt Clamp

INITIAL DATA

P - Axial load;

μ - Coefficient of friction on the clamping surface.

RESULTS DATA

F - Tightening force.

Metric Imperial

Load (P)

Friction coefficient (μ)

Tightening force (F)

BASIC FORMULAS

Tightening force:

F = 1.2*P / 2μ

INITIAL DATA

P - Axial load;

μ - Coefficient of friction on the clamping surface.

RESULTS DATA

F - Tightening force.

COEFFICIENTS OF FRICTION

Friction contact materials	Surface conditions	Friction coefficient
Steel-Steel	Dry	0.15
Steel-Steel	Greased	0.11
Steel – Cast iron	Dry	0.3
Steel - Copper	Dry	0.36
Steel - Copper	Greased	0.19
Steel - Bronze	Dry	0.12
Steel - Bronze	Greased	0.09
Steel - Brass	Dry	0.35
Steel - Brass	Greased	0.19
Steel - Titanium alloy	Dry	0.3÷0.7
Steel - Aluminium alloy	Dry	0.61
Bronze - Bronze	Greased	0.1
Cast iron - Bronze	Dry	0.22
Cast iron - Bronze	Greased	0.08
Cast iron – Cast iron	Dry	1.1
Cast iron – Cast iron	Greased	0.1
Aluminium alloy - Aluminium alloy	Dry	1.2
Aluminium alloy - Aluminium alloy	Greased	0.3
Titanium alloy – Titanium alloy	Dry	0.5

OTHER CALCULATORS

AREA MOMENTS OF INERTIA

BEAM CALCULATORS

TORSION OF BARS

CIRCULAR FLAT PLATES

BUCKLING

ELASTIC CONTACT

IMPACT LOADS

NATURAL FREQUENCIES

PRESSURED SHELLS

FLUID DYNAMIC

COMPOSITES

SPRINGS

THREAD CONNECTIONS

SHAFT CONNECTIONS

BEARINGS

DRIVES

FATIGUE

HEAT TRANSFER