How to Use a Torque-to-Angle Indicator

A torque wrench is a precision instrument that requires care to maintain accuracy.

Torque is a measure of pressure placed on a fastener. One foot pound of torque is equal to the pressure applied by a one foot lever with one pound of weight at the end. Every bolt and nut on a car has a limit to its strength. To avoid breaking bolts or leaving them too loose, manufacturers specify a torque value for tightening. To complicate matters, bolts tend to stretch as pressure is applied. Some are designed to stretch and snap back when the correct force is applied. A torque-to-angle indicator is used with a torque wrench to ensure the same amount of force is applied to each fastener.

Things You'll Need

• Torque wrench
• Torque angle indicator
• Socket set
• Torque specifications

Instructions

1. Follow the torque specifications to tighten each bolt or nut in the proper sequence with the torque wrench. Larger bolts are often tightened in stages, the higher the torque value, the more steps in the sequence. Go over the pattern again with the torque wrench in the same sequence and verify the torque reading for each bolt.

2. Fit the torque-to-angle indicator on the torque wrench and then attach the proper socket. Tighten each bolt to the angle specified by reading the angle indicator on the tool. Follow the same sequence used for all previous operations.

3. Verify your work by re-checking each bolt for proper torque with both the torque wrench and the torque-to-angle indicator.

Tips & Warnings

• Clean the threads of all fasteners to prevent erroneous readings.

• Support the head of the torque wrench.

• Periodically have your torque wrench calibrated.

• Do not re-use torque-to-yield bolts. Once tightened, they cannot hold proper torque again.

• Failure to follow the correct sequence can lead to a warped part or catastrophic failure.

References

• Federal Mogul Co
• CDX Online Textbook