# Numerical - Torque to overcome collar friction, given axial force & μ

Q.  Determine torque required to overcome collar friction in square threaded screw, if coefficient of friction is 0.12 and axial force of 20 kN is exerted by the screw. Mean radius of friction collar is 20 mm
- Published on 14 Sep 15

a. 48000 N-mm
b. 120 N-mm
c. 4800 N-mm
d. 12000 N-mm

#### Discussion

• Sravanthi   -Posted on 04 Nov 15
Given: Coefficient of friction (μ) = 0.12, axial force (W) = 20 x 103 N, mean radius of friction collar (Rm) = 20 mm

Formula: Torque required to overcome collar friction (T) = μ x W x Rm

here, μ = coefficient of friction, W = axial force, Rm = mean radius

Solution:

Substituting the given values we get,

(T) = μ x W x Rm

= 0.12 x 20 x 103 x 20

= 48000 N-mm

Torque required to overcome collar friction in square threaded screw is 48000 N-mm

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