Page 69 - CITS - Fitter - Trade Theory

FITTER - CITS

4 Thread micrometre
• Description: A thread micrometre is used to measure the pitch diameter or major diameter of screw
threads.
• Features: It has specially shaped measuring faces designed to fit the profile of screw threads. The
micrometre is placed over the thread, and the measuring faces are brought into contact with the thread
crests.
• Applications: Thread micrometres are commonly used in manufacturing, automotive, and aerospace
industries for measuring the pitch diameter of screw threads to ensure proper fit and functionality.
5 Digital micrometre
• Description: A digital micrometre is a modern variation of traditional micrometres that features a digital
readout for easier and more precise measurements.
• Features: It typically has an LCD display that shows the measurement in digital format, eliminating the
need to read scale divisions manually. Some digital micrometres also offer additional features such as data
output, zero-setting, and inch/metric conversion.
• Applications: Digital micrometres are used in various industries and applications where precise
measurements are required, offering faster and more accurate readings compared to traditional micrometres.

Principal of micrometre
Micrometres is a precision instrument operating on the principle of Nut-bolt
Safety precautions
1 The micrometres should be selected according to work
2 Micrometres should never be kept with other hand tool.
3 After use the micrometre should be cleaned & placed in the box with light oil.
4 Before using the micrometre it’s L.C zero error should be detected.

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CITS : CG & M - Fitter - Lesson 10