All About Screws
Every year, the screw manufacturer companies of the United States make around 200 billion fasteners. The screw, nut, and bolt revenue from all the screw manufacturer companies was $30 billion in 2017, and the industry employes 131,949 people. Read on to learn more about fastener options and history.
The idea of the screw has been around long before the first screw manufacturer actually began producing. It was around 200 BC that the first reference to the idea is to be found. In the beginning, all screws were custom screws in a sense, since all were handmade. No two were ever the same. It was not until 1928 that America’s screw manufacturer companies began producing standard sizes of screw. That’s the year the National Screw Thread Commission finally came up with a standard for threads that would make them interchangeable.
Types of Screws
Today’s screws come in a wide variety of options, from the micro plastic forming screw to custom shoulder bolts. Screws are described based on their thread lockers, their torque, pre-load measurements, and more.
The Hi-Lo Screw
One type of screw your screw manufacturer makes is called a hi-low. This type of screw has a minor diameter of reduced size. This means it displaces less plastic and stress on the screw is minimized. With a hi-li screw, the double lead is high and the thread low, and there is plenty of positive thread engagement.
This type of fastener has to pre-assembled parts that are combined by the screw manufacturer to produce a low-cost screw. There are washers under the head which make the SEMS screws fast to use and very adaptable.
The term breakaway torque refers to the torque needed to start a rotation when there is no axial load on the screw. The torque is measured between the fastener and the mating thread, and it does change with use. The breakaway torque is named by use as “1st Off,” 2nd Off,” and so on.
The term pre-load is used to refer to the axial load that is applied to a screw. This is measured in pounds per square inch, or psi, and comes from the applied seating torque. For most screws, a yield strength of 80% to 85% is considered appropriate.
The screw manufacturer of today is capable of producing enormous varieties of custom screw options for any imaginable application. This allows the screw to be perfectly fitted to the job it’s designed to do, which means greater efficiency and strength. The screw has come a long way since 200 BC. It’s now one of the most versatile and adaptable fasteners we have.