Page 40 - CITS - Fitter Trade Practical - Volume -2
P. 40
FITTER - CITS
MODULE 7
EXERCISE 62 : Mark off and drill through holes
Objectives
At the end of this exercise you shall be able to
• mark drill holes as per drawing
• drill through holes using pedestal drilling machine.
Job sequence
• Check the raw material for its size.
• File and finish to size 85 x 72 x 9 mm maintaining parallelism and perpendicularity.
• Mark drill holes as per drawing.
• Punch on drill hole centres using centre punch 90°
• Make centre drill in all drill hole centres.
• Fix 6 mm drill and drill pilot holes in all centre drilled holes.
• Similarly fix 8 mm, 10 mm, 12 mm and 16 mm drill in drilling machine and drill holes as per drawing.
• Finish file and de-burr in all the surfaces of the job.
• Check the size with vernier caliper.
• Apply a thin coat of oil and preserve it for evaluation.
25