Page 90 - CITS - Fitter Trade Pactical - Volume - 2

FITTER - CITS

EXERCISE 27: Relocating a wrongly positional drilled hole

& checking concentricity & dimension for
true drilling

Objectives

At the end of this exercise you shall be able to
• prepare round rod more than the hole size
• plug the hole as tight fit
• file the plugged surface on both sides flat and square
• mark the hole location concentricity to centre lines
• drill pilot and correct drill hole concentricity to the centre lines.

Job Sequence

• Check the given material hole size Fig 1.
• Punch on the drill hole centre mark with centre punch 90°.
• Fix centre drill in drill chuck and make centre drill hole.
• Fix Ø 6 mm drill and drill hole as a pilot hole
• Similarly fix Ø 9 mm, Ø 13 mm drill and enlarge the previously drilled holes.
• Prepare round rod more than 0.050 mm actual size of drilled hole (16.000 + 0.050 = 16.050 mm)
• Plug the hole as tight fit with prepared round rod using ball pein hammer (Fig 2).
• File the plug surface on both sides to flat and square.
• Apply marking media on surface.

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CITS : CG & M - Fitter - Exercise 26