Page 44 - CITS - Fitter Trade Practical - Volume -2

FITTER - CITS

Counter sink, counter bore and ream split fit (three
piece fitting)

Objectives: At the end of this exercise you shall be able to
• mark the lines as per job drawing
• drill, counter sink, counter bore and ream the holes as per drawing
• cut and remove excess metal in part 1 and 2
• file and finish to size and shape, make split fit as per drawing.
Job sequence

• Check the raw material for its size.
• File and finish to over all size of part 1 and 2 to 60 x 40 x 9 mm, part 3 to the size of 29 x 29 x 9 mm maintaining
parallelism and perpendicularity.
• Mark the hole centres and punch in part1 and 2 as per job drawing.
• Fix the job in drilling machine table with suitable clamps.
• Fix centre drill in drilling machine spindle through drill chuck and drill centre drilling in all drill holes centres.
• Fix Ø 6 mm drill in drill chuck and drill through holes as per drawing in all centre in drilled holes.
• Similarly, fix Ø 9.8 mm drill in drill chuck and drill through holes in ream hole locations.
• Fix counter sink tool in drilling machine and counter sink two holes to the required depth.
• Similarly, fix counter bore tool in drilling machine and counter bore two holes to the required depth.
• Ream in Ø 9.8 mm two drilled holes using Ø 10 mm hand reamer with wrench.
• Hold part 1 in bench vice.
• Cut and remove excess metal by hacksawing.
• File to size and shape as per job drawing.
• Similarly, repeat the above process in part 2 and complete the job.
• Mark the dimension lines as per drawing and punch witness marks in part 3.
• Cut and remove excess metal by sawing and file to size and shape as per drawing.
• Match part 1, 2 ,3 and make three pieces as split fit.
• De - burr in all the surfaces and corners of the jobs.
• Apply oil and preserve it for evaluation.

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CITS : C G & M - Fitter - Exercise 62