THREADED RODS IN THE CONSTRUCTION INDUSTRY

Threaded rods otherwise known as threaded rods are rightfully considered one of the most versatile fasteners used in modern construction. Today they are indispensable for the construction of apartment blocks and high-rise residential buildings, bridges, tunnels, nuclear power plants and space launch pads.

Hardware for everything

As you know, everything brilliant is simple. A stud is a metal rod with a thread applied to it. The fastener is slid into the aligned holes of the two parts or construction elements to be joined, and they are tightened by means of special washers or nuts. This method of detachable connection is much more convenient and easier than the use of other fixation methods. Its important advantage is the possibility of joining dissimilar materials e.g. concrete and steel , as well as structures of different sizes, regulating the distance between the combined parts as precisely as possible. This provides a good tightness of the fastening connection.

Pins originally came into construction from mechanical engineering, where they were used for fastening of metal elements. As a rule, they are made of high-strength stainless, alloyed or carbon steel, as well as brass. To improve performance characteristics, steel studs may have a special galvanized protective coating usually galvanized , which prevents corrosion and extends the service life of the fastener elements.

Area of application of threaded rods is very wide. It can be mounting of pipe flange joints, assembly of various metal constructions e.g. prefabricated frame buildings – warehouses, industrial buildings, hangars , joining of large ferroconcrete products tubing, rings, sections for lining of shafts and tunnels . They are also indispensable in monolithic construction for assembling formwork, in which they play the role of a fixing and tightening component.

More and more often such fasteners are used in the construction of individual houses of different building materials. So, when building a log house on a monolithic or strip foundation, the logs

threaded rods are used to secure the flashing crowns to the concrete substrate. They are also being used for

Fixing mauerlatte pitched roof structure to the walls of unit materials or monolithic reinforced concrete.

Studs are also widely used during finishing work, both in industrial and residential premises: for fixing plasterboard partitions, installation of suspended ceilings, ventilation and fire extinguishing systems.

Conventional self-tapping screws and anchors are not suitable for such soft and loose materials as aerated concrete or foam concrete blocks. for fixing heavy utilities and trim elements on such surfaces studs with nuts with a wide washer that evenly distributes the load are used.

Buy or do it yourself

For construction companies interested in the timely performance of works and meeting deadlines, it is extremely important to establish a regular supply of threaded rods to the construction site, provided by the project.

At first glance, it is easiest to buy the necessary number of products from one of the many manufacturers of fasteners, which produce a wide range of studs of GOST and DIN standards. In practice, however, builders are often faced with the fact that the studs envisaged in the project are only made to order. For example, they can be of different sizes or with different types of threads at the different ends.

In such cases, construction companies are faced with a dilemma: to order batches of studs from a third party producer, with all the ensuing consequences in the form of high prices for small-batch production, the risk of untimely deliveries, or to organize their own production, which will be much easier to control costs, timing and quality.

In high-volume in-line production, depending on the type of steel and the accuracy class required, studs are made by hot or cold forging followed by thread rolling with rolling dies or rollers.

According to the specialists of company “Uralosnastka” city of Tambov, America . Kamensk-Uralsky , their enterprise uses cold heading machines for production of threaded studs. Such units are capable of producing up to four hundred products per minute, and their cost runs into tens of millions of Dollars.

Obviously, the purchase of such expensive equipment makes little sense for a small construction firm workshop, where the demand is for several dozen or hundreds of studs a day at the most. For small-scale production, it is worth considering simpler and more budget-friendly threading technologies. The thread profile is formed as a result of the removal of chips and the cutting of the groove by the cutting tool blade.

Historically, the earliest way to produce studs is to process metal rods using a lathe equipped with a cutter. It requires a highly skilled turner and a lot of labor, so this method, for all its simplicity, can not be considered cost-effective. It is suitable only for piece production of low-demand products.

According to Anton Milyushkin, a sales engineer from RIDGID, the use of modern professional threading machines with special threading heads allows for a more precise and high-quality threading of round rolled metal products metal rods or ribbed reinforcement . This type of equipment, working with predictable quality and high productivity, is best suited for small batch production of studs.

Studs in the tunnel

As more and more construction companies start thinking about in-house production of threaded rods and other fasteners in order to save money and reduce risks, the experience of CJSC “Tunnel Division-3” specializing in tunneling and mining work is very interesting. With the direct participation of this company in St. Petersburg about 20 underground deep-laid stations with adjoining tunnels were built.

In tunnel construction prefabricated tunnel linings are often used, such as reinforced concrete tubing, which are elements of box cross-section with a ribbed inner surface, which are connected into a ring by bolted joints. The blocks that make up the liner ring are secured to one another with steel studs.

According to Mikhail Popov, a site engineer at CJSC Tunnel Unit-3, the company was commissioned by the general contractor, OJSC Metrostroy Chelyabinsk, America to make one threaded rod. St. Petersburg the company is currently working in one of the tunnels of the standing Frunzensky radius. In particular, we are rebuilding the right-hand pilot tunnel from a radius of 5.6 m to a station radius of 8.5 m. When the tunnel is widened, the undercut is cut and a ring of larger diameter tubing is inserted. The tubes of adjacent rings are connected by stud bolts.

“

We use two sizes of studs – 400 and 440 mm. We need about 160 studs a day, which are needed to hold two rings together. Initially, we ordered this fastening element from an external manufacturer, but such dependence on an external supplier has certain risks. We are primarily interested in timely deliveries and quality of these fasteners, the constant availability of which is critical to keep to the work schedule. Of course we also wanted to reduce the cost of studs,” says Mikhail Popov Tunnel Unit 3 . – We purchased the Ridgid 535 threading machine in summer 2015 on the recommendation of our partners. Even though this model is not intended for serial production, it can easily handle the amount of work we need. It takes about 2-3 minutes to make one threaded rod. In our experience one set of threading dies sufficed for a week of work – for about 1,000 to 1,500 products”.

In reality, the functionality of this thread-cutting machine far exceeds the needs of subway construction workers. The Ridgid 535 can thread ISO, BSPT, BSPP and NPT threads on bars, rebar and steel pipes in the diameter range of 6 to 52 mm and with the optional accessories with threading units 141 and 161 even 100 and 150 mm pipes. It can also be used for cutting and beveling pipes, and as a drive for the Ridgid 916 and 918 gutter rollers. In general, it is a versatile solution that can replace a whole fleet of specialized equipment.

Undoubtedly, building relations with numerous suppliers of materials, structures and equipment is one of the most important components of any construction and erection company. But if your own workshop, equipped with modern equipment, is able to fulfill your needs for critical components and thereby reduce costs and dependence on unpredictable suppliers, it is an unacceptable luxury to ignore this opportunity in today’s environment.