Question

In measuring the thread angle of a standard metric thread, the micrometer reading measured over the wires of 0.8660 and 1.4434 mm dia are 20.320 and 22.060 mm respectively. The flank angle is

• A. ${29}^{\circ }{46}^{\prime }$
• B. none
• C. ${59}^{\circ }{33}^{\prime }$
• D. ${59}^{\circ }{50}^{\prime }$

Answer 1

The correct option is C ${59}^{\circ }{33}^{\prime }$

$d_1=0.8660\text{mm}$

$d_2=1.4434\text{mm}$

$m_1=20.32\text{mm}$

$m_2=22.060\text{mm}$

$\sin \left(\frac{\theta }{2}\right)=\frac{d_2-d_1}{(m_2-m_1)-(d_2-d_1)}=0.4966$

$\theta ={59.5566}^{\circ }$

$\theta ={59}^{\circ }{33}^{\prime }$