A straight (concentric) extension, like the one displayed, can be used on a torque wrench and requires no change in torque value applied.

A straight (concentric) extension, like the one displayed, can be used on a torque wrench and requires no change in torque value applied.

• A. True
• B. False
• C. Not specified
• D. Sometimes

Answer: (A)

When a straight concentric extension is used, the torque wrench’s calibration stays valid because the force is transmitted along the same axis and the lever arm length effectively remains as the tool was designed for. In other words, the indicated torque at the dial translates directly to the torque at the fastener when the extension is inline with the drive. As long as the extension is fully seated and aligned, you don’t need to change the torque setting. If the extension were offset or at a different angle (like a crowfoot at 90 degrees), the lever arm would change and you would need to adjust the setting to achieve the same fastener torque. Minor variations can occur from minor misalignment or friction, but conceptually no change in the torque value is required with a straight concentric extension.

When a straight concentric extension is used, the torque wrench’s calibration stays valid because the force is transmitted along the same axis and the lever arm length effectively remains as the tool was designed for. In other words, the indicated torque at the dial translates directly to the torque at the fastener when the extension is inline with the drive. As long as the extension is fully seated and aligned, you don’t need to change the torque setting. If the extension were offset or at a different angle (like a crowfoot at 90 degrees), the lever arm would change and you would need to adjust the setting to achieve the same fastener torque. Minor variations can occur from minor misalignment or friction, but conceptually no change in the torque value is required with a straight concentric extension.