Next Generation Bolt Tightening

 Exploring The Most Popular Types Of Bolting Tightening Methods 

For many, it seems insignificant when a product is assembled with the support of nuts and bolts. However, the application of improper preload, as well as tightening methods can result in the breaking down of bolted joints. Adequately tightened bolts act like springs to generate joint preload and smoothen the workflow efficiently. Therefore, utilizing the most suitable bolt tightening methods is crucial to achieving a correct preload. Take an insight into this article to acknowledge the importance of bolt tightening methods and the different types of tightening procedures. 

Importance of bolt tightening methods 

• Safe and skilled operation 

The skilled operators follow definite procedures to tighten the bolt equipment in a more controlled way. Instead of relying on unsafe, uncontrolled manual tightening, the safe operation assures desired output.

• Reliable and consistent results 

Using measured and tested tools and proficient operators can repeatedly achieve reliable results. 

• Decreased operation fatigue

Displacing manual endeavors with bolt tooling will enhance productivity and reduce operator fatigue and bolt tightening timing. 

• Stability of bolt loading

For joints with gaskets, even compression is mandatory to stave off damage and help the gasket function efficiently.

Most common bolt tightening methods

Considering the industrial sector and its application, the following specific methods are used. 

• Turn-of-nut method or Angle control 

This precise yet simple bolt tightening method is applied for a definite tightening angle. This method is considered highly accurate for installing consistent preload and constructional bolts. This bolt-tightening method is widely used in automotive manufacturing. Here, the installation is made using the turn-of-nut tool. Since the new generation tools bring much flexibility, it helps achieve the specified angle turn. With active usage of digital torque wrench, bolt tightening is made. The main drawback of this method is settling in an accurate angle, which must be done via experimentation. 

• Torque tightening 

For preload management, the bolt torquing method is heavily used. Skilled operators hit the coveted torque value through the use of a calibrated torque wrench. Torque, the direct stress is enforced on the bolt heads to help compress the joint plates. To eliminate under head scraping, 50% of applied force is employed, and 40% of the torque is used to control thread friction. The rest, 10% of applied force, generates joint load. For efficient bolt tightening, hydraulic torque wrench, pneumatic torque wrench, and electric torque wrench are used. For safe, accurate tension, this is a comparatively low-cost method. To prevent severe preload shifting, a friction stabilizer is crucial. At the same time, employing flanged bolts and nuts helps increase accuracy. 

• Bolt stretching 

This method should apply to bolts with a diameter exceeding 20mm. These bolts require relatively high tightening torque. In this method, a hydraulic force is used on the nut, and an interlinked puller is getting attached to the force. The interlink section of the bolt has to elongate past the nut to make the bolt tightening successful. 

• Heat tightening 

For tightening huge bolts, this is the most accurate method. However, this bolting tightening method is used less than the other methods. This method employs thermal expansion of bolts, which means bolt heating with an open flame, covered carbon resistance elements, or heating coil to help it expand. From this point, the nut is labeled employing the path of the turn angle. It needs enough time for the system to settle down to cool. When the bolt gets contracted, the embedded material compresses it for preload generation. The biggest drawback of this bolt-tightening method is the bolt's length which is challenging to measure. The system must return to its surrounding temperature each time for accurate measurement. 

• Yield control tightening 

This bolt-tightening method seems accurate since it minimizes the impact of friction. This method is best used in conn-rod bolts and cylinder heads to achieve continuous high preload. The hand wrench is used and costs high compared to the traditional torque wrench. Thus, the adoption of this bolting tightening method is limited. This method provides a clear sense of the fastener's elasticity limit for minimum scatter and friction. This method emphasizes the craftsmanship of the "sense of feel" that allows the operator to pinpoint the yield point appropriately. 

• Tension indicating 

Tension indicating bolt tightening technique involves estimating bolt tension through load indicating washer, indicative load bolts, and the technique of calculating the fastener's length alteration. For effective bolt tensioning, there's a need for reliable tools that can be procured from renowned torque equipment manufacturers and suppliers. In this method, special bolts indicate the bolt's force. The load indicating washer is heavily used in civil engineering, and these washers come with small pipes which disfigure under the load. When a pre-decided gap is made between the bolt under head and washer that is when accurate preload is attained. 

Which bolt tensioning method is ideal for you?

With the help of advanced technology, engineers can resolve the issues associated with bolted joints and threaded fasteners. The designers must understand the specific features of the bolt tightening methods to achieve an accurate result. Since every bolt tensioning method has particular pros and cons, different industries adopt different bolt tightening methods for indisputable applications. Compare the bolt mentioned above tightening practices and consider your budget and unique needs to choose the most suitable solution for your application

Content Sources :- ABSGroup