If a torque wrench is miscalibrated and used to tighten a fastener, which outcome is most likely?

• A. The fastener will be fine
• B. The torque wrench will self-correct
• C. No effect
• D. The fastener may be under- or over-torqued, risking failure or looseness

Answer: (D)

The key idea is that a torque wrench that isn’t calibrated correctly won’t deliver the intended torque, so the fastener’s clamping force is unreliable. If the wrench reads a target value but is off, the actual torque may be higher or lower than what you need. Over-torquing can stretch the bolt, damage threads, or deform the fastener head, possibly leading to joint failure. Under-torquing reduces clamping force, allowing movement under vibration and increasing the risk of loosening, leaks, or fatigue failure in the joint. Since the tool won’t automatically adjust to compensate, the result is that the fastener ends up either under- or over-torqued, with real-world consequences for reliability and safety. The other choices imply no effect or self-correction, which isn’t the case with a miscalibrated torque wrench.