If you need to provide bolt tensioning or torqueing, which will be the better option? Even though objective of both the actions is same, tensioning is better option to create better clamping force to hold both the parts together. However, sometimes it may not be practical or may not be necessary at all. Therefore, you must choose which method is possible and better for certain applications.
Let’s talk about tensioning
You must have heard about hydraulic tensioners where high pressure fluid is used (oil in most cases), which creates the necessary force to stretch the bolt while the nut is turned. Here the main objective is to stretch the bolt or the stud with the help of tensioning by providing certain amount of calibrated load, which is done by using certain force to elongate the shank.
Hydraulic cylinder is used for creating the force for both pulling and pushing. After that it is possible to put the nut manually by using a wrench. You will not need too much turning force to tighten the nut. Little bit of extra threading is necessary above the nut that can be used for attaching the pulling cylinder and after the completion of the job, cylinder can be removed.
What are the main attributes?
- Highly accurate
- Ease of control and stability
- Little expensive as compared to any other system
- Useful for fitting larger sized bolts
The objective here remains the same that is to stretch the stud or bolt to certain predetermined load. Here the stretching is done by rotating the nut and shank gets pulled owing to the threads of ramp angle.
During torqueing the nut rotates against the surface of the bolt or stud which is to be clamped. As you increase the clamp load, the friction between nut and surface of bolt or stud increases to certain pre-determined amount.
Following are the attributes
- More versatile
- Less expensive to make the arrangement
- Less accurate as compared hydraulic way of tensioning
- Simple to use
- Suitable for smaller fasteners
You can decide which type of tool will be needed for achieving the necessary load on the clamp will depend on the engineering specifications. In case tensioning is recommended then it must be chosen. If torque is suggested then it is possible to employ tensioning, if handy. Many torque specifications permit broader accuracy making tensioning redundant.