ASME B107.300 recognizes four primary types of torque wrenches, each with different mechanisms, accuracy requirements, and calibration characteristics. Understanding the differences matters both for choosing the right tool and for knowing what to expect when it comes time to calibrate.
The Four Types
Type 1
Click-Type Torque Wrench
The most common type in general shop and fleet use. When the preset torque is reached, an internal mechanism releases with an audible and tactile click. The technician stops applying force at the click.
The mechanism relies on a calibrated spring and pivot — which makes it effective but also sensitive to drops, overloading, and improper storage. This is the type we see fail most frequently in calibration.
The mechanism relies on a calibrated spring and pivot — which makes it effective but also sensitive to drops, overloading, and improper storage. This is the type we see fail most frequently in calibration.
ASME Tolerance
±4% of reading
Test Direction
CW (+ CCW if reversible)
Calibration Risk
High — drops, storage
Type 2
Dial-Type Torque Wrench
A dial indicator on the head displays real-time torque as it's being applied. No click — the technician watches the needle and stops at the target value. More forgiving for applications where torque needs to be held at a specific value rather than just reached.
Generally more stable than click-type wrenches because there's no spring-loaded release mechanism. The flex beam and dial mechanism is less sensitive to drops but still requires calibration verification.
Generally more stable than click-type wrenches because there's no spring-loaded release mechanism. The flex beam and dial mechanism is less sensitive to drops but still requires calibration verification.
ASME Tolerance
±4% of reading
Test Direction
CW (+ CCW if dual-direction)
Calibration Risk
Moderate
Type 3
Beam-Type Torque Wrench
The simplest mechanical design. A flex beam deflects as torque is applied, and a pointer tracks against a fixed scale. No spring mechanism, no electronics — inherently simple and durable.
Beam wrenches are arguably the most stable type from a calibration standpoint because there's nothing to drift except the beam itself. They're less convenient than click or dial types but often used as reference tools precisely because of their stability.
Beam wrenches are arguably the most stable type from a calibration standpoint because there's nothing to drift except the beam itself. They're less convenient than click or dial types but often used as reference tools precisely because of their stability.
ASME Tolerance
±4% of reading
Test Direction
CW
Calibration Risk
Low
Type 4
Electronic / Digital Torque Wrench
Uses a strain gauge sensor to measure torque electronically, displaying the value digitally. Can typically store readings, set alerts, and connect to data systems. Often capable of accurate bidirectional measurement.
Tighter tolerance requirement under ASME — ±2% vs ±4% for mechanical types — reflecting the higher precision capability of electronic measurement. More expensive, more capable, and requires calibration of the electronic chain in addition to the mechanical components.
Tighter tolerance requirement under ASME — ±2% vs ±4% for mechanical types — reflecting the higher precision capability of electronic measurement. More expensive, more capable, and requires calibration of the electronic chain in addition to the mechanical components.
ASME Tolerance
±2% of reading
Test Direction
CW and CCW
Calibration Risk
Low-Moderate
Which Type Should You Use?
The right wrench depends on your application, budget, and documentation requirements:
- Click-type — best for high-volume fastening where speed matters and the tactile click is important for workflow. Most common in automotive, fleet, and general mechanical work.
- Dial-type — good for applications where you need to hold a specific torque value, watch the approach, or verify torque on existing fasteners.
- Beam-type — excellent for low-volume, high-stakes applications where you want maximum stability and simplicity. Often used as a check against click-type wrenches.
- Electronic — best for production environments with data logging requirements, torque traceability demands, or applications requiring the tighter ±2% tolerance.
For most shops: Click-type for general work, electronic when documentation or precision demands it. Whatever type you use — calibrate it. All four types drift, just at different rates and for different reasons.
Calibration Differences by Type
While all four types are calibrated against the same ASME B107.300 test points (20%, 60%, 100% of capacity), the calibration process and failure patterns differ:
- Click-type — most likely to fail after drops or storage under tension. Often adjustable in-house.
- Dial-type — typically fails gradually. The dial face can be re-zeroed but significant drift requires repair or replacement.
- Beam-type — rarely fails calibration unless physically damaged. Long service life between adjustments.
- Electronic — sensor calibration drifts slowly; more likely to fail due to connector issues, battery problems, or physical damage. Some require factory service for adjustment.
All Four Types — We Calibrate Them All
Click, dial, beam, and electronic torque wrenches up to 600 ft-lb. Pick up and drop off within 24 hours.
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