Question

In a bolted joint two smooth members are connected with an axial tightening force of $2200N$.If the bolt used has metric threads of $4mm$ pitch, the torque required for achieving the tightening force is

• A. $0.7Nm$
• B. $1.0Nm$
• C. $2.8Nm$
• D. $1.4Nm$

Answer 1

The correct option is D $1.4Nm$


Tightening force =$2200N$
Pitch =$0.004m$
For single strat thread
Lead= Pitch
$\tan \alpha =\frac{L}{\pi D_m}=\frac{pitch}{\pi D_m}$
$T=\frac{W{D}_m}{2}\times \tan (\varphi +\alpha )$
For smooth thread , $\varphi =0$ [given in question]
$T=\frac{W{D}_m}{2}\times \frac{Pith}{\pi D_m}$
$=W\times \frac{Pitch}{2\pi }$
$=2200\times \frac{0.004}{2\pi }=1.4Nm$