How to Use a Flat-Beam Torque Wrench

A flat-beam torque wrench is used to tighten nuts and bolts to a pre-set forque setting.

The flat-beam torque wrench was invented in 1918 by Conrad Bahr, and perfected by P.A. Sturtevant of Chrysler Engineering. The tool has no moving parts. Torque is measured by the amount of deflection imposed on a ground alloy steel beam while under load. The tool is accurate to within 2 percent in both directions, it is maintenance-free and only requires calibration after extended use. The flat-beam torque wrench has an indefinite service life. For example, the U.S. government has only had to replace one flat-beam torque wrench used daily since World War II. Using the device isn't difficult.

Things You'll Need

• Socket

Instructions

1. Fit the correct-size torque wrench socket onto the square lug at the working end of the torque wrench.

2. Place the socket on the nut or bolt to be torqued.

3. Grasp the pivoting handle in one hand and steady the socket end with the other, with the wrench extended to the right. Pull the wrench handle toward you to tighten the fastener.

4. Read the amount of torque imposed by monitoring the movement of the pointer over a calibrated scale mounted near the wrench handle. When the pointer lines up with the required torque setting, release the pressure on the handle and remove the socket from the nut or bolt.

References

• Sturtevant Richmont: M Series Memory Flat Beam Torque Wrenches
• Park Tool: Torque Specifications and Concepts
• Web Bike World: Torque Wrench