Types of torque wrenches
What is a Torque Wrench?
A torque wrench is a tool used to tighten a nut or bolt to a desired value, such as the lug nuts which hold a tire onto a vehicle. When a specific tightness is desired to prevent nuts or bolts from becoming loose and an object collapsing or falling off, then a torque wrench is the needed tool to get the job done correctly.
Different Types of Torque Wrenches
There are four different types of torque wrenches. While no one type is deemed ‘the best’, the price, usage and style differences often dictate which one is purchased.
Beam Torque Wrench
A beam style is the least expensive and will handle most jobs related to automotive maintenance.
Click Torque Wrench
A click adjustable torque wrench is the type most often used by mechanics. Twisting the handle changes the torque value of the wrench. This kind of wrench has an internal spring and adjustable handle for easy usage. A click torque wrench allows you to check the torque by feel instead of by sight. This is great for when the wrench is in a tight space.
Dial & Electronic Torque Wrenches
The dial or electronic gauge types are typically only used by (or needed by) professional mechanics in the race car industry.
Dial wrenches and electronic wrenches are the most accurate types of torque wrench. Their gauges are incredibly easy to read which makes for quick work. These high-end wrenches can go for just over a hundred bucks to several thousands of dollars.
Who Needs a Torque Wrench?
If you are performing repairs or maintenance on a vehicle you’ll need a torque wrench. They can enable you to tighten nuts and bolts to a specified value. They also prevent over-tightening, which could cause nuts and bolts to stretch, strip or break.
What Can Torque Wrenches Do?
In addition to tightening the lug nuts that hold tires in place, a torque wrench will also be needed for several automotive repair tasks. All the critical fasteners on a vehicle will need a torque wrench for proper installation. In addition to lug nuts, a torque wrench will be needed for ball joint studs, axle nuts, exhaust manifold bolts, flywheel bolts, bolts on the crankshaft pulley, and many others.
How Do Torque Wrenches Work?
Put simply, these tools multiply the force that we are able to generate with our hands.
Torque wrenches are calibrated to apply a pre-calculated amount of load to bolts and nuts. The calculation is affected by the length of the wrench and how much force you need to use.
The force you apply with your manpower (or womanpower as the case may be) when pressing down on the wrench handle will determine how much torque is being applied to tighten or loosen the nut or bolt. Too much pressure and the bolt or nut can strip or break, too little pressure and the bolt won’t budge.
A torque wrench has either a scale or a display on the handle of the tool. This lets you know the amount of pressure or load the wrench is applying. Scales are usually calibrated in three different units of measure – foot-pounds (ft. lbs.), inch-pounds (in. lbs.) and Newton-meters (Nm). Most automobile torque wrenches will have a dual scale that shows torque measurements in both NM and FTlbs.
How to Use a Torque Wrench
You will need to know the torque specifications for the bolt before attempting to tighten it with a torque wrench. Guessing is not allowed, specifics are required and are easy to find out with a quick online search or flip through the automotive manual. Skipping this step and using the wrong torque specification can result in expensive damage later on.
All bolts must go in clean, dry and damage-free. If they’re not, the pre-calculated values will be off. There is one exception to that rule and that is for cylinder head bolts. These need to be given a light coat of oil before tightening.
Start the installing the nut or bolt with a traditional rachet or socket wrench until it is snug, but not overly tight. Next comes the usage of the torque wrench to tighten the nut or bolt to the required specifications.
Tightening Lug Nuts
The most frequent usage for all types of torque wrenches is for securing lug nuts into place. Securing the lug nuts into place at the proper amount of torque prevents uneven wear on the rotors, breaking off a wheel stud or losing a wheel while driving down the road.
Certain types of bolts, such as those which secure a manifold into place, require that the bolts be tightened in a certain sequence so castings and gaskets are not damaged. Follow manufacturer’s directions regarding tightening sequence.