Even experienced mechanics sometimes develop bad habits with torque wrenches—habits that compromise accuracy, damage equipment, or create safety hazards. Whether you're new to torque tools or a seasoned professional, reviewing these common mistakes helps ensure you're getting the most from your precision equipment. Here are the ten most frequent torque wrench errors and, more importantly, how to avoid them.
Mistake #1: Storing Click-Type Wrenches at High Settings
This is perhaps the most widespread torque wrench mistake. Many users finish a job, set their wrench aside, and don't think about it again until the next use. The problem? Click-type torque wrenches use an internal spring mechanism, and leaving the wrench set at working torque keeps that spring compressed—sometimes for weeks or months.
Over time, spring compression causes fatigue and permanent set, degrading accuracy. A wrench stored at 100 Nm might only deliver 90 Nm after repeated storage under tension.
âś“ The Fix
Always return your click-type torque wrench to its lowest setting after use. Make this step as automatic as putting the cap back on a pen. The few seconds it takes preserves calibration and extends tool life significantly.
Mistake #2: Using a Torque Wrench as a Breaker Bar
A torque wrench is designed to apply controlled force, not to break loose seized or corroded fasteners. Using it to crack stuck bolts subjects the precision mechanism to shock loads and forces far exceeding its design parameters.
The consequences include damaged internal components, bent handles, lost calibration, and in extreme cases, complete tool failure. Even if the wrench appears undamaged, accuracy may be compromised.
âś“ The Fix
Use a proper breaker bar to loosen fasteners first. Your torque wrench should only be used in its intended direction—tightening—and within its specified capacity. Treat it as the precision instrument it is.
Mistake #3: Continuing to Apply Force After the Click
When a click-type torque wrench reaches its set value, it produces a distinctive "click" and slight handle movement. The instinctive response for many users is to feel this click and then apply one more "just to be sure." This practice, sometimes called "double-clicking" or "clicking past," results in over-torquing.
Each click past the set point adds additional torque. What you thought was 100 Nm might actually be 110 or 120 Nm after multiple clicks—enough to stretch fasteners, warp components, or strip threads.
âś“ The Fix
Develop the habit of stopping immediately at the click. Your hands should relax the instant you feel and hear the mechanism release. Practice on non-critical fasteners until this becomes automatic. Trust your tool—one click means the job is done.
Mistake #4: Ignoring Calibration Requirements
Torque wrenches are precision instruments that drift out of specification over time and with use. Many users buy a wrench, use it for years, and never verify calibration. They assume that because the click mechanism still works, the readings must be accurate.
In reality, an uncalibrated wrench can be significantly inaccurate while appearing to function normally. You might be consistently under or over-torquing fasteners without knowing it.
âś“ The Fix
Have your torque wrench calibrated annually, or after every 5,000 cycles for heavy use. Calibration is inexpensive compared to the cost of damage from incorrect torque. Keep calibration records and mark your wrench with the next due date. Read our calibration guide for more information.
Mistake #5: Applying Force Away from the Handle Grip Point
Torque wrenches are calibrated assuming force is applied at a specific point—usually the centre of the grip area. Applying force elsewhere changes the effective lever arm length and produces inaccurate results.
Gripping too far up the handle (toward the head) reduces effective torque. Gripping the very end or using extensions on the handle increases effective torque. Neither produces the reading shown on the scale.
âś“ The Fix
Always apply force at the designated grip point, typically marked or textured on the handle. Pull perpendicular to the handle axis for best results. Never use pipe extensions or "cheater bars" on torque wrench handles.
Mistake #6: Neglecting Thread Condition and Lubrication
The relationship between applied torque and resulting clamping force depends heavily on friction. Dirty, rusty, or damaged threads dramatically increase friction, meaning less of your applied torque converts to useful clamping force. Conversely, lubricated threads reduce friction, potentially causing over-tightening at the same torque value.
Specifications typically assume either "dry" threads or specify when lubrication should be used. Ignoring these details leads to inconsistent results.
âś“ The Fix
Clean threads with a wire brush or thread chaser before assembly. Check whether your specification is for dry or lubricated conditions. If lubricant is specified, use exactly what's recommended. If using anti-seize or thread locker when not specified, reduce torque by approximately 25%.
Mistake #7: Not Following Tightening Sequences
Multi-bolt patterns—cylinder heads, wheels, flanges—require specific tightening sequences to ensure even clamping force distribution. Tightening bolts randomly or in a circular pattern can result in warped components, uneven gasket compression, and premature failure.
Even when using correct torque values, wrong sequence can leave some bolts taking more load than others, leading to localised stress and potential joint failure.
âś“ The Fix
Always look up and follow manufacturer-specified tightening sequences. For wheel nuts, use a star (criss-cross) pattern. For rectangular or long components, typically start from the centre and work outward. When in doubt, tighten in multiple passes—snug first, then final torque.
Mistake #8: Using the Wrong Size Wrench for the Job
Torque wrenches have an accuracy "sweet spot"—typically between 20% and 80% of their maximum capacity. Using a 200 Nm wrench to torque a 20 Nm fastener (10% of capacity) produces unreliable results. Similarly, a 100 Nm wrench used at its maximum is less accurate than one rated higher operating in its optimal range.
The wrong drive size also matters—using a 1/2" drive wrench with adapters for every job wastes accuracy and makes access difficult in tight spaces.
âś“ The Fix
Select a torque wrench where your target value falls between 20-80% of capacity. For varied work, maintain wrenches covering different ranges. Match drive size to the application—1/4" for small fasteners, 3/8" for general work, 1/2" for automotive and larger applications.
Mistake #9: Confusing Torque Units
Torque specifications come in various units: Newton-metres (Nm), foot-pounds (ft-lb), inch-pounds (in-lb), and occasionally kilogram-force metres (kgf-m). Confusing these units leads to dramatically incorrect torque.
For example, 100 ft-lb equals approximately 136 Nm. Applying 100 Nm when 100 ft-lb is specified under-torques the fastener by about 26%—potentially dangerous for safety-critical applications.
âś“ The Fix
Before setting your wrench, verify both the specification unit and your wrench's display unit. Many digital wrenches can switch between units—ensure you're using the correct one. When converting, use a calculator rather than estimating. Read our guide on torque specifications for conversion factors.
Mistake #10: Not Verifying Critical Fasteners
A single torque operation is generally reliable, but for critical applications—wheel nuts, suspension components, cylinder heads—verification provides crucial peace of mind. Many users torque once and move on, never confirming their work.
Fasteners can settle, threads can compress, and gaskets can seat further after initial torquing. Without re-verification, you might not achieve final intended clamping force.
âś“ The Fix
For critical fasteners, re-check torque after a settling period. Wheel nuts should be verified after 50-100 km of driving. Cylinder head bolts often require re-torquing after a heat cycle. Make this verification step part of your standard procedure for safety-critical work.
Building Good Habits
Avoiding these mistakes comes down to treating your torque wrench as the precision instrument it is and following methodical procedures. Here's a checklist for every torquing operation:
- Select the appropriate wrench for the torque range and drive size
- Verify calibration status
- Confirm specification unit matches your wrench setting
- Inspect and prepare fastener threads
- Set correct torque value
- Follow proper sequence for multi-bolt patterns
- Apply smooth, controlled force at the grip point
- Stop immediately at the click (for click-type)
- Verify critical fasteners after settling
- Return wrench to lowest setting before storage
By avoiding these common mistakes and following best practices, you'll get accurate, reliable results from your torque wrench—protecting your equipment, your work, and your safety. Precision fastening isn't difficult; it just requires attention to detail and respect for proper technique.