|3. Screw: Screw is used to hold different parts of machines together. It simply consists of a threaded rod with a head called a screw head.
Pitch of Screw: Consider a screw in figure, the distance between the two consecutive threads of a screw is known as pitch.
Mechanical Advantage of Screw: Consider a screw as shown in figure of radius ‘d’ and pitch ‘h’. Screw driver applies an effort of ‘P’ at the screw head to hold the load ‘W’. If screw turns one time then effort moves distance of 2πd and load is lowered a distance of ‘h’
The above equation shows the mechanical advantage of a screw will increase as its radius is greater and pitch is lower.