Overview

Your challenge is to design a device that interacts with a $\backslash (3/8^\{\backslash$prime $\backslash$prime$\}\backslash )$ drive socket to tighten a nut or bolt to a specified torque. When the required torque is met the fishing line in the device should break to prevent overtightening.

Requirements

$-$ The device must be able to achieve torque values of $10,20,$ and $40$ lb $-$ ft with minimal adjustment.

$-$ The device must be a hand tool that fits in a toolbox; no electricity or compressed air allowed.

$-$ The device must be operable by a single person.

$-$ No materials can be swapped out to achieve the different torque settings $($e$.$g$.$ the tensile strength of the fishing line is constant$).$ However, the fishing line can change length slightly to accommodate different torque settings.

$-$ The device must interface with a $\backslash (3/8\backslash )"$ drive socket $($see Fig. $1)$