Screws are an important part of the family of threaded fasteners that include nuts, bolts, studs, and some highly specialized screws that find applications in the automotive and aerospace industry. There are mainly 2 types of screws – wood screws and machine screws. The threads on them might run in any way including straight, parallel, tempered, left, or right-handed. Both types of screws are made of metals. However, the machine screws have a constant diameter while wood screws are tapered making a grip to the wood surface.
A look at the history of screws
The history of screws goes back to around 200 B.C. The range of nuts, bolts, and screws made and supplied by the leading standard and weld bolt manufacturers that we see today was developed only after the Renaissance. In those days, no two screws used to be alike because all of them were hand-crafted. The extremely time-killing process of handcrafting as well as filing the threads into the screws had made it almost impossible to mass-produce the screws.
It was the year 1586 when a court engineer for Charles IX of France invented the first screw-cutting machine paving the way for more innovations in the times to come. The name of that engineer was Jacques Bessen.
Today’s scenario in screws manufacturing
In contemporary times, thread rolling has completely replaced the machining of screws. It was developed by an American named William Keane in the year 1836. At that time, the thread rolling procedure was not considered to be very good as the iron metal utilized to make the thread-rolled screws used to be low grade showing symptoms of splitting during the die-cutting process. Therefore, the eventual need for mass-producing a huge quantity of screws at cost-effective prices resulted in constant revaluation as well as accomplishment of thread-rolling manufacturing of screws.
Raw materials required for manufacturing
Almost all the leading standard and self-tapping screw manufacturers in India make use of low to medium carbon steel wire to manufacture screws. However, as per the nature of the application and specific requirements, some other tougher yet inexpensive metals are also substituted to serve the purpose. The substitutions of metals include:
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Industrial-grade stainless steel
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Brass
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Nickel alloys, or Aluminum alloy.
While choosing any metal to manufacture screws, quality is maintained well.
Designing Process
The designing process of screws as adopted by the leading socket head bolt manufacturers is that - on a single thread screw, pitch and lead are quite identical where lead is just twice the pitch on a double thread model. The pitch of a screw is the distance between two grooves. It is also well known as the number of threads per inch. The length of the wire is cut to length by the cold heading machine making two blows on the end resulting in the head. Next, in the head slotting machine, blanks are clamped in the threads around the perimeter. A circular cutter does the slotting of the screws with the revolution of the wheel.
A summary of the screw production process that most standard and self-tapping screw manufacturers undertake is as follows:
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Wire – the wire is uncoiled, straightened, and cut to length
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Cold forging - molding of the material is done to give it the right shape
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Bolt head – formed progressively by forcing the material into different types of dies at high pressure
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Threading - Threads are created either by rolling or cutting
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Heat treatment - The item is exposed to high heat to harden the material (majorly steel)
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Surface treatment - Depending on the application, the surface treatment is given. Zinc-plating is most common as it increases the corrosion resistance
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Packing/stocking - After a comprehensive quality control inspection for ensuring uniformity and consistency, the screws, nuts, and bolts are packaged.
Sometimes to give additional finishing to the screws, Zinc, Chrome, and Black Oxide are also used. They provide the screws with durability and corrosion resistance.
Here are some finishing materials used by the leading socket head bolt manufacturer in the final finishing of screws:
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Zinc: Applied as fine white dust, zinc coating on screws acts as a sacrificial anode that safeguards the underlying metal.
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Chrome: Applied by electroplating, chrome coating is used to give screws a bright and reflective finish. This coating is well known for its decorative and durable characteristics.
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Black oxide: Also known as processed black rust, Black Oxide coating is most commonly utilized to take care of the aesthetic aspects of the screws. This coating does not enlarge the dimensions of the product.
Some most commonly used screws
Made and supplied by the leading screw manufacturers in India, some of the most used screws in our day to day life include wood screws, wing screws, thumb screws, shoulder screws, sheet metal screws, set screws, self-drilling screws, particle board screws, mirror screws, machine screws, masonry screws, Jack screws, dry-wall screws, drive screws, dowel screws, deck screws, and cap screws. Some industries use only customized screws that are manufactured on special orders by the leading industrial screw manufacturers in India such as Super Screws. High-quality industrial-grade raw material is used to make them.
Applications of screws
Screws manufactured and supplied by the top standard and self-tapping screw manufacturers are used in the following conditions:
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When 2 parts to be fastened are too thick to accommodate the threaded hole.
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The situations where there is no place for nut accommodation
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When the parts to be fastened are strong enough to accommodate durable threads
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When the parts to be fastened are seldom dismantled.
Concluding Remarks
Founded in the year 1976, Super Screws is one of the largest bolts and screws manufacturers in India. Currently, Super Screws is producing the widest range of precision cold-forged low and high tensile industrial fasteners along with industry-specific solutions. OEMs make up the largest segment (90%) of the company’s clients. Its products and solutions are therefore geared towards adding value to its clients’ operations by providing them with superior engineering expertise, increasing supply chain efficiency, and reducing costs.