1. Introduction
Thank you for choosing the WORKPRO 3/8'' Square Drive Torque Wrench. This precision tool is engineered for accurate torque application in various mechanical tasks, particularly in automotive and general repair. To ensure safe and effective operation, please read this manual thoroughly before use and keep it for future reference.
2. Safety Information
WARNINGS:
- DO NOT overtighten the part you are installing. It may damage the part and cause serious injury. Stop tightening parts upon hearing the "click" sound of the torque wrench. Continuing to exert force after the "click" has sounded will affect calibration of the wrench and will damage the wrench beyond repair.
- Never use the torque wrench to undo or loosen bolts, nuts or fasteners. This may damage the mechanism and the calibrated settings.
- DO NOT add a sleeve or extended arm at the end of the torque wrench. This may damage the torque wrench.
- Do NOT tilt the wrench handle when using. This will lead to torque deviation and fastener damage.
3. Product Overview & Components
The WORKPRO Torque Wrench features a robust design for reliable performance:
- Drive Size: 3/8" Square Drive
- Torque Range: 5-100 Ft-lb (19-110 Nm)
- Ratchet Head: 24-Tooth, 40CR material, heat treated, black surface treatment, with a 15° swing arc for tight spaces. Made from Chrome Molybdenum Steel (Cr-Mo) for durability.
- Handle: Carbon steel body with an effective anti-corrosion, non-slip knurled aluminum handle for a secure grip.
- Calibration: Clear, easy-to-read dual-range scale (Ft.lb/Nm) for precise settings, even in low light conditions.
- Mechanism: Features a reversible switch for changing direction and a locking mechanism to prevent accidental torque setting changes. The 'click-stop' mechanism provides an audible and tactile alert when the preset torque is reached.
- Overall Length: Approximately 370mm ± 5mm (14.6 inches).
4. Setup
- Unpacking: Carefully remove the torque wrench from its blow-molded storage case.
- Setting Torque:
- Locate the locking mechanism at the base of the handle (see Figure 5).
- Unlock the handle by rotating the locking knob.
- Rotate the handle to adjust the torque setting. Align the desired torque value on the main scale with the mark on the handle. The dual-range scale allows setting in both Ft.lb and Nm.
- Once the desired torque is set, lock the handle by rotating the locking knob back into the locked position to prevent accidental changes during use.
5. Operating Instructions
- Attach Socket: Securely attach the appropriate 3/8" drive socket to the square drive on the ratchet head.
- Select Direction: Use the reversible switch on the ratchet head to select the desired direction of rotation. For tightening, ensure the switch is set for clockwise rotation. The counter-clockwise direction should only be used as a normal wrench for loosening, not for applying precise torque.
- Apply Force: Place the socket onto the fastener. Apply smooth, steady, and increasing force to the wrench handle. Ensure you are holding the wrench by the non-slip handle and not tilting it.
- Click-Stop Mechanism: Continue applying force until you hear and feel a distinct "click" from the wrench. This indicates that the preset torque value has been reached. Immediately stop applying force.
- Do Not Overtighten: Exceeding the click will damage the fastener and the wrench's calibration. Refer to the safety warnings.
6. Maintenance & Storage
- Cleaning: After each use, wipe the torque wrench clean with a soft, dry cloth. Do not use harsh chemicals, solvents, or abrasive materials, as these can damage the finish and calibration.
- Storage: Always store the torque wrench in its original blow-molded case when not in use. This protects it from dust, moisture, and physical damage, helping to maintain its accuracy and extend its lifespan. Store in a dry, clean environment.
7. Specifications
| Feature | Detail |
|---|---|
| Drive Size | 3/8 inch Square Drive |
| Torque Range | 5-100 Ft-lb (19-110 Nm) |
| Ratchet Teeth | 24-Tooth |
| Ratchet Head Material | 40CR, heat treated, black surface, Chrome Molybdenum Steel (Cr-Mo) |
| Handle Material | Carbon steel, knurled aluminum (non-slip) |
| Overall Length | 370mm ± 5mm (approx. 14.6 inches) |
| Accuracy | ±4% calibration range |
| Product Weight | 0.87 kg |
| Package Dimensions | 40cm (L) x 7cm (W) x 8cm (H) |
| Origin | Mainland China |
8. Troubleshooting
- Wrench not clicking at desired torque: Ensure the locking mechanism is fully engaged after setting the torque. Verify that no extended arm or sleeve is being used, and the handle is not tilted, as these can affect accuracy. If the issue persists, the wrench may require recalibration or professional service.
- Damage to fasteners: This often indicates overtightening or an incorrect torque setting. Always stop immediately after the distinct "click" sound. Double-check the required torque specification for your application.
- Wrench feels loose or mechanism is not engaging: Do not use the torque wrench to loosen fasteners, as this can damage the internal mechanism and affect its precision. Use a standard wrench for loosening tasks.
9. User Tips
Based on available user feedback and common inquiries, here are some general tips:
- Always ensure the torque wrench is clean and free of debris before and after use.
- When setting the torque, rotate the handle smoothly to avoid overshooting the desired value.
- For critical applications, it is good practice to periodically check the wrench's calibration with a certified calibration device.
- The weight of the wrench is approximately 0.87 kg, which provides a good balance of durability and manageability for various tasks.
10. Warranty & Support
WORKPRO stands behind the quality of its products. For warranty information, technical support, or service inquiries, please refer to the contact information provided with your purchase or visit the official WORKPRO website. Please have your product model and purchase details ready when contacting support.
