A torque wrench works by applying a pre-set amount of rotational force (torque) to a fastener—most commonly bolts or nuts. The goal is to tighten without over-tightening, which can prevent thread stripping, component failure, or dangerous loosening over time.
There are several mechanisms that determine how a torque wrench functions and how consistently it can deliver the target torque:
Internal Mechanism Type
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Click-Type: Uses a calibrated spring and clutch to produce a tactile "click" at the target torque. Calibration quality and spring integrity greatly affect accuracy.
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Beam-Type: Uses a steel beam that bends under load; the pointer indicates torque. Simple, durable, but harder to read precisely.
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Digital/Electronic: Uses strain gauges and sensors to digitally measure torque—often with data logging, which is useful for traceability.
High-end digital models (like Norbar or Snap-on) offer real-time feedback, data export, and angle measurement, reducing human error and increasing auditability. This is now found more often with an App for Digital Torque wrench - helping you with useful functions like Torque and Angle, Torque before Angle etc.
Build Quality & Calibration
The most accurate torque wrenches are:
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Machined to tight tolerances
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Calibrated in ISO 6789-certified labs
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Built using hardened, low-friction internal components
Premium brands often include a certificate of calibration traceable to international standards. Lower-end tools may not even allow recalibration.
Repeatability is also an important aspect of torque measurement - especially when you have removable heads to suit different types of applications.
Materials Used: What makes it better
Material selection affects a variety of critical areas for torque measurement. This is because torque wrenches are used over long periods of time in demanding conditions.
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Thermal expansion
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Corrosion resistance
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Long-term accuracy
For example: Brands like Norbar use aircraft-grade aluminum and precision steel alloys for consistent performance across various temperatures and environments. This means more accurate measurement with better durability.
