TB Break-Over Torque Wrenches

Quick Answer

The TB is a compact preset break-over torque wrench designed for repetitive production fastening at a predetermined torque value.

When the preset torque is reached, the wrench breaks over, signaling the operator to stop applying force. This helps reduce the risk of over- and under-tightening while supporting repeatable, controlled fastening.

Unlike the TBIH, the TB is configured with a fixed head that is permanently attached to the wrench. The head type and size are selected when configuring the tool and cannot be interchanged after assembly.

Who This Is For

Manufacturing engineers
Process engineers
Quality engineers
Assembly operators
Production supervisors
Electronics manufacturers
Medical device manufacturers
Aerospace manufacturers
Automotive manufacturers
General industrial assembly facilities

When Should You Use This?

Use the TB when:

Repetitive fastening is performed at the same torque setting
A dedicated wrench configuration is preferred
Low- to medium-torque fastening is required
Over- and under-tightening need to be controlled
Preventing routine operator torque adjustment is important
A compact wrench is needed for restricted spaces
The application uses a consistent fastener type and size
A permanently attached wrench head is suitable for the process

Preset torque wrenches are particularly useful when operators repeatedly assemble parts at the same torque setting.

When Should You NOT Use This?

The TB may not be the best choice when:

Operators need to frequently change torque settings
Different wrench heads need to be used with the same handle
An adjustable wrench with a visible torque scale is required
Torque requirements exceed the TB range
Electronic torque measurement or fastening data collection is needed
Counterclockwise torque application is required

If you need the ability to remove and change wrench heads, consider the TBIH Break-Over Wrench instead. The TB has a permanently attached head, while the TBIH uses removable interchangeable heads.

How the TB Works

The TB uses a preset break-over mechanism to provide a clear indication when the target torque has been reached.

During operation:

The wrench is preset to the required torque value.
The operator applies torque to the fastener.
When the preset torque is reached, the wrench breaks over.
The break-over action signals the operator to stop applying force.
The wrench is then ready for the next fastening cycle.

Result:

Reduced risk of over-tightening
Reduced risk of under-tightening
Repeatable application of preset torque
Improved operator consistency
Better control of repetitive fastening processes

The break-over mechanism also helps minimize shock to the assembly.

Core Features

Preset break-over torque wrench
Permanently attached fixed head
Configurable head type and size
Torque range from 25 ozf.in to 50 lbf.in
Break-over mechanism signals when preset torque is reached
Helps reduce over- and under-tightening
Tamper-resistant internal torque adjustment
No external adjustment scale
Small and lightweight design
Designed for restricted spaces
Six colored aluminum handle options for production identification
Designed for repetitive production fastening
Meets ISO 6789:2017 accuracy and repeatability requirements at ±6% of setting

The data sheet specifically identifies repeatability, traceability, and precision as benefits of the TB design.

TB Wrench Configuration

The TB is a made-to-order configurable wrench. Four elements are selected to create the finished wrench and its part number:

Wrench handle torque capacity
Handle color
Wrench head type
Wrench head size

Once configured, the selected wrench head is permanently attached to the TB handle.

Available Torque Ranges

Configuration	Torque Range	S.I. Range
0600A	25–50 ozf.in	17.7–35.3 cN·m
0600B	3–12 lbf.in	33.9–135.6 cN·m
0600C	12–21 lbf.in	135.6–237.3 cN·m
0600D	25–50 lbf.in	226–565 cN·m

Note: The current Mountz product page lists the highest configuration as 20–50 lbf.in, while the 2021 data sheet lists 25–50 lbf.in for 0600D. I would use 20–50 lbf.in in the Knowledge Base if you want it aligned with the current product listing.

Model Selection Guide

If you need:	Recommended Configuration
Lowest torque fastening	0600A
Low-torque fastening	0600B
Low- to medium-torque fastening	0600C
Highest TB torque capacity	0600D
Dedicated production identification	Select the appropriate handle color
Dedicated fastener configuration	Select the required fixed head type and size

Handle Color Options

The TB is available with six colored aluminum handles that can be used to visually identify different torque settings, applications, assembly stations, or production processes.

Handle Color	Configuration Number
Black	1
Blue	2
Red	3
Green	4
Gold	5
Silver	6

TB Fixed Head Options

The TB is configured with a permanently attached wrench head selected for the fastening application.

Available head types include:

Head Type	Configuration	Best For
Open End	OE	General fastening and applications requiring side access
Box End	BE	Increased fastener engagement and control
Hex Key	HK	Internal hex fasteners
Flare End	FE	Fasteners around tubing, lines, or obstructions
Ratchet	RH	Applications requiring repeated tightening without repositioning the wrench

The data sheet provides numerous imperial and metric sizes depending on the selected head style.

Open End Heads

Open end heads are available in imperial and metric configurations, with the data sheet listing sizes from 5/64" through 7/8" and 3 mm through 22 mm.

Box End Heads

Box end heads are available in multiple imperial and metric sizes for applications requiring greater fastener engagement.

Hex Key Heads

Hex key configurations support internal hex fasteners and are available in both imperial and metric sizes.

Flare End Heads

Flare end configurations are designed for applications where tubing, lines, or other components limit access around the fastener.

Ratchet Head

The TB can also be configured with a 52-tooth, 1/4" female hex ratchet head.

TB vs. TBIH

The main difference between the TB and TBIH is the wrench head design.

Feature	TB	TBIH
Torque Type	Preset	Preset
Break-Over Mechanism	Yes	Yes
Head Style	Fixed	Interchangeable
Head Selected for Application	Yes	Yes
Head Removable After Assembly	No	Yes
Best For	Dedicated repetitive fastening	Applications requiring head flexibility

Choose the TB when the same head type and size will be used consistently.

Choose the TBIH when you need the flexibility to remove the wrench head and install another option.

Setup & Torque Adjustment

The TB does not have an external torque scale. Its torque value is set using an internal adjustment mechanism and must be verified with a torque analyzer.

For calibration and adjustment:

Select a torque tester or sensor that covers the TB's torque range.
Connect the wrench using the appropriate adapter.
Apply torque clockwise slowly and smoothly until the wrench breaks over.
Note the measured torque value.
Adjust the internal torque setting as required.
Repeat the test and adjustment until the desired torque value is achieved.
Verify the setting before placing the wrench into production.

Mountz specifies using Peak mode when calibrating break-over torque wrenches with a digital torque tester or sensor.

Calibration & Accuracy

The TB should be periodically calibrated and verified as part of the facility's torque control program.

Mountz specifies the TB as meeting or exceeding the accuracy and repeatability requirements of ISO 6789:2017 at ±6% of setting.

The TB is calibrated in the clockwise direction only. Mountz's TB FAQ also notes that ISO 6789-1:2017 calls for a maximum of 5,000 cycles before recalibration.

Common Applications

The TB is commonly used in:

Electronics assembly
Medical device manufacturing
Aerospace assembly
Automotive manufacturing
Instrumentation and precision equipment assembly
General industrial production
Restricted or confined assembly areas
Repetitive production fastening
Dedicated fastening stations
Applications requiring preset torque with a fixed head

Use Cases (Real-World Examples)

Repetitive Production Fastening

Problem: Operators repeatedly tighten the same fastener to the same torque value.

Solution: The TB provides a dedicated preset torque setting and fixed head configuration, helping improve consistency across repetitive fastening cycles.

Restricted Assembly Areas

Problem: Limited workspace makes larger torque wrenches difficult to operate.

Solution: The TB's compact, lightweight design makes it suitable for fastening applications with restricted access. Current product information lists the handle at approximately 5 inches long and 9/16 inch in diameter.

Production Error-Proofing

Problem: Operators can accidentally change adjustable torque settings during production.

Solution: The TB uses an internal torque adjustment with no external scale, helping prevent routine operator adjustment once the wrench has been configured and verified.

Dedicated Fastening Station

Problem: A workstation repeatedly uses the same fastener type, size, and torque value.

Solution: The TB can be configured with the required fixed head, torque capacity, and handle color to create a dedicated fastening tool for that process.

Maintenance

Keep the wrench clean and free of debris.
Inspect the handle, break-over mechanism, pivot point, and fixed wrench head for wear or damage.
Periodically verify torque output using a calibrated torque analyzer.
Recalibrate according to your facility's calibration schedule and applicable quality requirements.
Verify torque after changing the internal preset value.
Apply torque smoothly at the proper load point when testing or calibrating the wrench.
Remove damaged or improperly functioning tools from service until inspected or repaired.

Integration & Advanced Notes

Mechanical preset torque wrench requiring no electrical power
Fixed head permanently attached to the wrench
Multiple head styles and sizes available when configuring the tool
Internal torque adjustment helps prevent unauthorized setting changes
Six handle colors support visual production identification
Designed for repetitive fastening at a predetermined torque
Clockwise calibration
Compact design for restricted assembly areas
Made-to-order configuration allows torque capacity, handle color, head style, and head size to be selected for the application

Media & Supporting Content

Need Help?

Contact Applications Engineering for torque range, fixed head configuration, and application guidance.
Speak with Sales for product selection assistance
- Call us:
  - North America:(408) 850-9978
  - International: +44 1428 741756

TB Break-Over Torque Wrenches – FAQ & User Guide