Talking torque with HTC: #3 Torque Tool Types

CONTINUING FROM OUR PREVIOUS ARTICLE WHERE WE LOOKED AT WHAT HAPPENS WHEN WE APPLY TORQUE, THIS TIME LET’S REVIEW THE COMMON TYPES OF TOOLS ON THE MARKET

Manual Torque Wrenches

Click, break-back, or dial/digital wrenches are by far the most common tools, from small screwdrivers to large break-back style wrenches used on truck wheel lugs.

As the name implies, these wrenches are human powered and the effort involved is proportional to the length of the tool. Screwdrivers are governed by how much force can be generated in a hand twisting action. Commonly ranging from 0 – 1500Nm with ¼ to 1-inch square drives, these tools provide readings for the operator to monitor as they go.

Powered Tools

There are basically two categories of powered tool — hydraulic and powered multiplier. These tools can produce staggering amounts of force and, rather than transferring any force to or from the operator, they send it to an integral reaction foot. The reaction foot is the common component on all powered tools, and must be transferred somewhere like a flange or the next bolt.

• Hydraulic wrenches: These generate large forces from small packages which makes them perfect for a wide range of bolting applications, especially where space is limited. The catch is that they use a ratchet mechanism so can only move one click at a time. To run the wrench also requires a pump and twin hose and the operator cycles the pump back and forth to tighten the bolt.

• Manual multipliers: A torque multiplier, as the name infers, is a gearbox that takes a small force and multiplies it by a set ratio. Input force needs to be applied using a torque wrench so that the output force can be controlled, and breakages avoided.

• Powered multipliers: Imagine the above manual multiplier, but with a power input. This allows for much faster, continual turn fastening and removes virtually all effort from the operator.

Choosing the correct tool for the job is critical to avoid expensive issues. For this we weigh up simple metrics, like the type and size of the bolts, quantity per day, conditions, and how long a project will run for. It is also critical that equipment is serviced and calibrated on a cycle that is suited to the conditions and site usage levels. In the next edition we will cover what is involved and best practice for calibrating and servicing your tools.

HTC Ltd is New Zealand’s leading supplier of torque wrench tools and calibration, servicing, and repair services. To book a calibration service for your torque tools, visit htc.co.nz/calibration-and-testing/ and scroll down to the booking form. To contact the team directly, call 0800 48 2000.