Page 49 - CITS - Fitter Trade Practical - Volume -2
P. 49

FITTER - CITS


           Drill through hole and blind holes

           Objectives: At the end of this exercise you shall be able to
           •   mark drill hole centres using vernier height gauge
           •   set the correct spindle speed in drilling machine
           •   drill through hole as per drawing
           •   set the depth bar to drill blind hole
           •   drill blind hole to the required depth size.





































            Job sequence


           •   Check the raw material size.
           •   File and finish the metal to size 60 x 60 x 19 mm maintaining parallelism and perpendicularity.
           •   Check the flatness and squareness with try square and size with vernier caliper.
           •   Apply marking media and mark drill holes centres using vernier height gauge as per drawing.
           •   Punch on drill holes centres using centre punch 90°

           •   Hold the job in drilling machine table.
           •   Make centre drill in drill holes centres.
           •   Fix Ø 6mm drill in drilling machine spindle through drill chuck and drill pilot holes for both through and blind
              holes.
           •   Fix Ø 8.5 mm drill and drill through hole as per drawing.
           •   Fix Ø 10.5 mm drill and drill blind hole to the required depth of 14 mm.
           •   File and de - burr in all the surfaces of the job.

           •   Apply a thin coat of oil and preserve it for evaluation.







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                                            CITS : C G & M - Fitter - Exercise 62
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