Screw You use screws every single day — you just don’t notice them. They’re inside your phone, furniture, motorcycles, cars, computers, door locks, home appliances, factory machines, medical instruments…Small as they are, without screws, the world simply cannot be assembled, cannot operate, and cannot be repaired. This article will help you understand screws quickly — their functions, materials, and where they are used. --- 1. What is a screw and why is it important? A screw

In hardware parts, machining, and equipment maintenance, it’s common to encounter a confusing situation: you only want to find a screw or a pin, yet the specifications appear in two completely different formats — one written as M4, M6, M8 (metric), and another as 1/4"-20 or #8-32 (imperial). Many people wonder:“Why aren’t these specifications unified?”“Since they look similar, can they substitute for each other?” The answer is: No.Metric and imperial systems differ in units,