Most systems save time in spending turning raw materials into components, but the next production step is often assembling and fastening those additives together. fee, weight, electricity, availability, reliability, corrosion resistance and ease are a number of the many factors that have an impact on the fastening technique. There are more than a hundred particular fastening designs and tens of hundreds of variations when duration, give up and material are counted. three factors decide whether or not or not a fastening is a screw or bolt. • length: Screws are normally under ¼ " in diameter; bolts are large. • Mating threads: Screws healthful threads tapered right right into a workpiece; bolts healthful into a mating nut. this is generally, however now not always, actual. • Head design: Screws are frequently slotted; bolts regularly have rectangular or hex heads. In the passage with the difference amongst stress and head layout, power design is the outside or inner form at the fa