EXAMPLE $8-1$ A square$-$thread power screw has a major diameter of $32mm$ and a pitch of $4mm$

with double threads, and it is to be used in an application similar to that in Fig. $8-4.$

The given data include $f=f_c=0\mathrm{.}08,d_c=40mm,$ and $F=6\mathrm{.}4kN$ per screw.

$($a$)$ Find the thread depth, thread width, pitch diameter, minor diameter, and lead.

$($b$)$ Find the torque required to raise and lower the load.

$($c$)$ Find the efficiency during lifting the load.

$($d$)$ Find the body stresses, torsional and compressive.

$($e$)$ Find the bearing stress.

$(f)$ Find the thread stresses bending at the root, shear at the root, and von Mises stress

and maximum shear stress at the same location.