Metric fasteners are fasteners that are manufactured and labeled in accordance with the global measurement standard. This global standard is set by the International Organization for Standardization (ISO), which is based in Geneva, Switzerland. This world standard is based on the metric system.
There are many ways to mount and manufacture fasteners for sizes
It is important to have some kind of standard screw with a variety of products and equipment that rely on screws to quickly together. The United Kingdom, the United States and Canada invented a faster measurement system in 1949 called the Unified Thread Standard. They hoped that this would become a world standard. But ISO standards have finally won. The United Kingdom no longer uses this standard at all, and Canada is currently in the middle of a transition to the ISO standard of standard closure. Today, 40% of screws and products made in the USA are manufactured with faster metric systems. Gradually, metric fasteners replace UTS fasteners. Soon the UTS will go out.
Metric fasteners are measured in millimeters from its thread diameter from edge to edge, and not part of a screw rod. Capital letter “M” will precede the number of millimeters of width that the flow has. For example, a metric closure may be 5 millimeters wide and is denoted as M5. 6 mm wide thread is designated M6.
Metric fasteners had two levels of thread thickness
Thin and thick. None of them was better or worse than the other, but they are incompatible. Thus, ISO decided to use thin threaded screws as standard. Today, most new products are made with thin threads in mind, but can still get thick threads, because some old products that use rough threads still need to be repaired from time to time.
More specifically, in the manufacture of fasteners, screws and bolts, metric fasteners are largely controlled by the automotive industry. Let’s start with the design and development. In the 70s, many companies are still in the project, however, today we use CAD systems that not only allow us to draw shapes, not climbing, but also easily switch between English systems and measurement metrics. However, technical specifications are still difficult to obtain in metric terms. Why is there no IFI standard for hexagonal metric washers when one of them is available in inches?
The workshop and production process are full of measurement gaps in English. Converting to inches reduces one tenth of the rounding tolerances. Lathes, milling machines, grinding machines and other tools, equipment manufacturing and a group of supporting dial indicators and scale measurement, based on the English system. All equipment and measuring instruments, such as calipers, micrometers and test equipment, such as torque wrenches, use the English measurement system and must be replaced by their metric system with their equivalents.