When To Use A Hydraulic Torque Wrench For Bolting

Co-Written by Dan Johnson & Rob Rohena

How You Typically Thread Joints Together

The most common way to apply rotational force to the head of a bolt is to apply “load” and twist, which will allow it to move slightly closer to the nut with each torque.

This process is typically done manually with an allen wrench, monkey wrench, socket wrench, or other hand held wrench.

However, when dealing with tight spaces, industrial machinery, or heavy duty projects — human-powered wrenches are seldom a viable option for three reasons:

  1. the application of force required is greater than every the world’s strongest men can provided
  2. the angle you need to correctly install the bolt into the nut is not level, therefore can result in faulty alignment, or bolt failure.
  3. the method you are using is unsafe, which can lead to you pinching your hand, busting your knuckles, or worst.

At this point your best options could include:

  • a pneumatic impact wrench.
  • a bolt tensioners
  • a hydraulic torque wrench

For the purposes of this article, we will focus on the latter option for getting the job done safely and efficiently.

A brief history of the hydraulic torque wrench

According to Wikipedia, a hydraulic torque wrench is a power tool designed to exert torque on a fastener to achieve proper tightening or loosening of a connection through the use of hydraulics. A torque wrench is applied to the nut either directly or in conjunction with an impact socket.

Hydraulic torque wrenches apply a predetermined, controlled amount of torque to a properly lubricated fastener. [1]

The Hydraulic Torque Wrench was invented in Houston by George A.

The wrenches were first launched in the market in early 1960’s in basic form.

Since it introduction in the early 1960s, the hydraulic torque wrench has seen many technological advancements.

Some of these changes have been made for safety and ergonomics, others for convenience and economic gain.

Today’s hydraulic torque wrench features lighter weight, actuation that triggers the tools, small nose radius for tight spaces, multi-position reaction members and the capability of operation multiple tools at the same time from a 10,000 PSI single hydraulic torque power pack, like the TORC Dynamic.

Types of hydraulic torque wrench for precision boltings

The following characteristics set the hydraulic torque apart from other types of torque wrench and tightening tools:

  • Use of only hydraulics
  • Self-ratcheting
  • Accurate method of determining the amount of applied torque

Why and When to use a hydraulic torque wrench for the job

As stated earlier, a hydraulic torque wrench provides that high amount of torque you need for increased clamping force.

That is, these torque tools use hydraulics to exert torque on a fastener.

This “torque” is the compressive force that a fastener exerts on a joint.

In essence a hydraulic torque wrench is a tool designed to exert torque on a fastener to achieve proper tightening or loosening of a connection through the use of hydraulics.

Best of all, hydraulic torque wrenches apply a controlled and predetermined amount of torque.

As the hydraulic fluid pressure increases, so does the torque applied to the bolt.

You’ll get accurate and consistent torque values since we know hydraulic fluid won’t compress.

That’s why torque has been the go-to means of controlling clamping force and bolt loading.

Finding the right hydraulic torque wrench size for the job.

Standard torque tables point us to the proper amount of torque we use for each specific size and grade of bolt.

[You can FREE download torque conversation charts from our resource center].

However, if you need to spec the proper torque for a given application, a number of factors need to be considered to ensure the torque applied will result in the correct amount of clamping force.

  • How many times has the bolt been used?
  • Are the bolt and nut truly clean?
  • Any lubricant applied to the threads and nut face?
  • Are you using flat washers?
  • What finish is used on the bolts?
  • Do the bolt and nut match in terms of finish and grade?



2 thoughts on “When To Use A Hydraulic Torque Wrench For Bolting”

  1. Pingback: When and How To Use A Hydraulic Bolt Tensioner For Bolting

  2. Pingback: Hydraulic Bolt Tensioner : When Accuracy Is Not An Option

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