Page 160 - CITS - Fitter Trade Pactical - Volume - 2

FITTER - CITS

EXERCISE 45: Exercise on advance practice on drilling,

counter sinking, tapping etc

Objectives

At the end of this exercise you shall be able to
• file and finish flat surfaces within an accuracy of ± 0.02 mm
• mark and drill holes as per drawing
• calculate Tap drill size
• cut internal thread to assemble countersink screws
• use counter sunk drill.

Procedure

• Check the raw material for its size.
• Remove scaling surface using rough file.

• File the top surface with a flat bastard file 250mm.
• Check flatness with a try-square.
• File to medium finish using a flat second cut file 250mm.
• Check the flatness of surface using try square.
• Remove high spot using second cut file 250mm and check flatness again.

• Repeat this activity until surface make parallel .
• Check flatness using try square.
• file longer side using second cut file 250mm.

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