Using a longer lever on a torque wrench will cause the wrench reading to be lower than the actual bolt torque for a fixed target torque.

Using a longer lever on a torque wrench will cause the wrench reading to be lower than the actual bolt torque for a fixed target torque.

• A. Higher than actual torque
• B. Lower than actual torque
• C. Equal to actual torque
• D. Unreliable torque reading

Answer: (B)

Torque is the product of force and the lever arm. A torque wrench is calibrated for a specific handle length, so the reading on its scale corresponds to a certain torque when you apply force at that length. If you add a longer lever (an extension), the same force produces more torque than the wrench is calibrated to indicate. In that situation, the bolt ends up with more torque than the wrench shows—the reading is lower than the actual torque delivered. So, for a given target torque, using a longer lever makes the wrench under-read versus what the bolt actually experiences. As a practical note, extensions or adapters should be avoided or accounted for, because they alter the effective lever arm and can lead to over-torquing if not compensated.

Torque is the product of force and the lever arm. A torque wrench is calibrated for a specific handle length, so the reading on its scale corresponds to a certain torque when you apply force at that length.

If you add a longer lever (an extension), the same force produces more torque than the wrench is calibrated to indicate. In that situation, the bolt ends up with more torque than the wrench shows—the reading is lower than the actual torque delivered. So, for a given target torque, using a longer lever makes the wrench under-read versus what the bolt actually experiences.

As a practical note, extensions or adapters should be avoided or accounted for, because they alter the effective lever arm and can lead to over-torquing if not compensated.