Podcast
Questions and Answers
What type of nuts typically require lower torque values?
What type of nuts typically require lower torque values?
- Shear nuts (correct)
- Pipe union nuts
- Critical bolted joints
- Bolted joints
What is the purpose of a torque wrench?
What is the purpose of a torque wrench?
- To measure the length of a fastener
- To determine the material of a fastener
- To measure the amount of torque required to turn a fastener (correct)
- To apply a fixed amount of force to a fastener
Why is correct torquing important for bolts?
Why is correct torquing important for bolts?
- To ensure the bolt is subject to its metallic stress strain (correct)
- To ensure the bolt is over-torqued
- To ensure the bolt is not subject to any stress
- To ensure the bolt is tightened loosely
How is the amount of torque calculated?
How is the amount of torque calculated?
How should a torque wrench (except dial type) be held to operate accurately?
How should a torque wrench (except dial type) be held to operate accurately?
What type of torque wrench uses a beam that deflects under load?
What type of torque wrench uses a beam that deflects under load?
What is a unique characteristic of PLI washers?
What is a unique characteristic of PLI washers?
Why is accurate measurement essential in aircraft maintenance?
Why is accurate measurement essential in aircraft maintenance?
What is the first step in using a precision measuring instrument?
What is the first step in using a precision measuring instrument?
What is required to ensure precision measuring instruments are reliable?
What is required to ensure precision measuring instruments are reliable?
Why is it important to observe in-service limits?
Why is it important to observe in-service limits?
What should a technician do if a precision measuring instrument does not zero correctly?
What should a technician do if a precision measuring instrument does not zero correctly?
What is the pitch of the spindle of the English micrometer?
What is the pitch of the spindle of the English micrometer?
What does each vertical line on the sleeve of the English micrometer designate?
What does each vertical line on the sleeve of the English micrometer designate?
What is the distance moved by the spindle longitudinally when the thimble is rotated from one division to the next?
What is the distance moved by the spindle longitudinally when the thimble is rotated from one division to the next?
What is the total distance represented by 25 divisions on the thimble?
What is the total distance represented by 25 divisions on the thimble?
What is the typical range increment of metric micrometers?
What is the typical range increment of metric micrometers?
What is the purpose of the vernier scale on a micrometer?
What is the purpose of the vernier scale on a micrometer?
When using a micrometer other than 0–25 mm, what must be added to the reading on the scale?
When using a micrometer other than 0–25 mm, what must be added to the reading on the scale?
How do you read the metric Vernier micrometer scale?
How do you read the metric Vernier micrometer scale?
What type of micrometer gives a digital read-out of measurements?
What type of micrometer gives a digital read-out of measurements?
What is the accuracy of measurements using a Vernier micrometer?
What is the accuracy of measurements using a Vernier micrometer?
What is the primary purpose of the internal micrometer?
What is the primary purpose of the internal micrometer?
What is the range of the sleeve scale on an internal micrometer?
What is the range of the sleeve scale on an internal micrometer?
What is the purpose of the collar on an internal micrometer?
What is the purpose of the collar on an internal micrometer?
What is used to lock the collar in place on an internal micrometer?
What is used to lock the collar in place on an internal micrometer?
What determines the measuring range of an internal micrometer?
What determines the measuring range of an internal micrometer?
What is the purpose of the extension rods on an internal micrometer?
What is the purpose of the extension rods on an internal micrometer?
Study Notes
Shear Nuts and Torque Values
- Lower torque values are critical for shear nuts and pipe union nuts to prevent failure.
- Accurate torque application is essential for the integrity of fasteners, particularly in aviation.
Torque Wrenches
- Torque wrenches measure the amount of torque needed to turn fasteners.
- The force required to turn is directly related to the internal tensile stress within the fastener.
- Torque is calculated as the product of applied force and lever arm length, where lever arm is the distance from the applied force to the driving adapter.
- Proper handling is required for accurate torque measurement, especially with non-dial types, which should be held at the knurled handle.
Types of Torque Wrenches
- Deflecting Beam Type Wrench: This flexible beam type measures torque through deflection; it must be replaced after use due to compression.
- PLI (Preload Indicating) Washers are used in critical bolted joints with self-locking nuts, indicating when proper preload has been achieved.
Calibration and Precision Measurements
- Precision measurements are vital in aircraft maintenance to ensure correct part fit and compliance with dimensional tolerances.
- Technicians must verify measurement tools by zeroing them before use; instruments that do not zero correctly require calibration.
- Regular inspection and calibration of precision measuring tools are essential for maintaining accuracy in measurements.
Standard English Micrometer
- English micrometers feature a spindle with a thread of 40 TPI, allowing precise measurement of 0.025 inches per complete revolution.
- The sleeve divides the measurement into major divisions of 0.100 inches and smaller divisions of 0.001 inches.
- Reading a micrometer involves noting major divisions and counting smaller divisions to achieve a precise measurement down to thousands of an inch.
Metric Micrometers
- Metric micrometers are available in increments of 25 mm, with specific ranges for accurate measurement of internal and external dimensions.
- The gap in the frame must be added to readings when using micrometers outside of the 0–25 mm range.
Vernier and Electronic Micrometers
- Some micrometers are equipped with a vernier scale, providing measurements to an accuracy of 0.002 mm.
- Electronic micrometers modernize measurement processes, allowing for quick conversions between imperial and metric systems.
Internal Micrometers
- Internal micrometers measure internal dimensions and consist of a measuring head with extension rods.
- The measuring range can be adjusted by varying the length of the rods and attaching collars as needed.
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Description
Test your knowledge of torque values and fastener applications in aircraft maintenance, including shear nuts and pipe union nuts. Learn about the importance of correct torquing and the use of torque wrenches and preload indicating washers.
