7.3.6 Torque Wrenches

Question 1

What is a Torque Wrench?

Answer 1

A Torque Wrench is a tool that applies a specific torque or load to a fastener such as a bolt, nut, or screw. These tools are essential in Aircraft maintenance to achieve the design specifications of the concerned parts and structure.

Question 2

How are Torque Wrenches classified according to ISO 6789?

Answer 2

Torque Wrenches are classified into two types: Type 1 (Indicating) and Type 2 (Setting).

Question 3

What are the characteristics of Type 1 Torque Wrenches?

Answer 3

Type 1 Torque Wrenches indicate the torque to the user via a mechanical scale, dial, or electronically. The operator must stop at the desired torque without visual, feel, or audible aids.

Question 4

What are the characteristics of Type 2 Torque Wrenches?

Answer 4

Type 2 Torque Wrenches are either fixed or adjustable to a pre-set torque value. They indicate when the pre-set torque is reached through audible, visible signals, or feel.

Question 5

What is a Flex Bar Torque Wrench (Class A)?

Answer 5

The Flex Bar Torque Wrench, also known as a Deflecting Beam torque wrench, is rarely seen today and is susceptible to damage. It is usually restricted to workshop environments.

Question 6

What is a Dial Indicating Torque Wrench (Class B)?

Answer 6

This Dial Indicating wrench is more common and robust but can be challenging to read in restricted spaces.

Question 7

What is an Electronic Torque Wrench (Class C)?

Answer 7

This type of torque wrench provides clear indication once the desired torque is achieved, often with audible signals.

Question 8

What is a Ratchet Click Type Torque Wrench (Class A Type 2)?

Answer 8

This is the most common type of Torque Wrench, adjustable and indicates the desired torque by a clicking sound.

Question 9

What is a Fixed Torque Wrench (Class B Type 2)?

Answer 9

A Fixed Torque Wrench is set at manufacture to a specific value and is used for one task only, with no adjustable scale.

Question 10

What is the significance of torque in mechanics?

Answer 10

Torque is a rotational or twisting force intended to rotate or turn a fastener, also referred to as the moment of force.

Question 11

How is torque measured?

Answer 11

Torque is expressed in SI units (Newton Meters) or Imperial units (pounds feet, pounds inch).

Question 12

What are the storage guidelines for Torque Wrenches?

Answer 12

Keep them in original packaging, store in a clean area, clean before storage, and return adjustable wrenches to the lowest setting.

Question 13

What should be checked before using a Torque Wrench?

Answer 13

Inspect for damage, check calibration labels, ensure the torque to be applied is within the wrench’s range, and verify the correct units of measure.

Question 14

What should be ensured when applying final torque to an aircraft wheel?

Answer 14

The final torque should be applied in one smooth action without the need to ratchet the torque wrench back for reapplication. Ensure the position of the torque wrench allows maximum swing.

Question 15

What should you do once the torque has been indicated by a click?

Answer 15

STOP IMMEDIATELY.

Question 16

What is the lever arm in relation to a torque wrench?

Answer 16

The lever arm, L1 nominal length, is the specific length from the centre of the drive holding the socket to the handle of the torque wrench.

Question 17

What happens to the torque setting when an extension is added to a torque wrench?

Answer 17

Adding an extension increases the lever arm to L2 extended length, which in turn increases any torque setting made on the torque wrench.

Question 18

What must an Aircraft Engineer ensure regarding fasteners?

Answer 18

No over torquing of fasteners occurs, as it can go unnoticed and fail later while in service.

Question 19

How should the prescribed torque be adjusted when using an extension?

Answer 19

The prescribed torque must be reduced due to the increased lever arm caused by the extension.

Question 20

What is the torque setting of the wrench denoted as?

Answer 20

M1 is the Torque setting of the wrench.

Question 21

What is the actual torque applied to the fastener denoted as?

Answer 21

M2 is the actual Torque applied to the fastener.

Question 22

What is the nominal length of the Torque Wrench denoted as?

Answer 22

L1 is the nominal length of the Torque Wrench.

Question 23

What is the extended length of the Torque Wrench denoted as?

Answer 23

L2 is the extended length of the Torque Wrench.

Question 24

What happens when an extension is placed at 90° to the torque wrench arm?

Answer 24

The centre of the fastener remains on the same plane as the torque wrench, so the torque value specified can be used without any change.

Question 25

What is required for extensions positioned at angles other than 90°?

Answer 25

A torque calculation is required for extensions where the position of the adapter is not at the extended or 90° positions.

Question 26

What does T1 represent in torque calculations?

Answer 26

T1 is the torque specified for the fastener.

Question 27

What does L represent in torque calculations?

Answer 27

L is the nominal length of the Torque Wrench.

Question 28

What does C represent in torque calculations?

Answer 28

C is the change in length because of the tool added to the drive of the Torque Wrench.

Question 29

What does T2 represent in torque calculations?

Answer 29

T2 is the corrected torque setting for the Torque Wrench.

Question 30

What is an example of an app that can calculate torque values?

Answer 30

Norbar Torque Wrench Extension App.

Question 31

What is the torque-angle tightening method?

Answer 31

This method uses initial torque loading but for a final torque, it gives an angle that has to be used instead of a torque value.

Question 32

What do some aircraft wheel manufacturers specify for wheel tie bolts?

Answer 32

Both torque values and torque angles, allowing the operator to choose which method to use.