Page 47 - CITS - Fitter Trade Practical - Volume -2

FITTER - CITS

Fig 3

Fig 4

Use the depth stop arrangement for controlling the depth of the counterbore hole.
Check the depth of the counterbored hole. (Use the correct screw for checking the depth and seating).

Reaming drilled holes using hand reamers

Objectives: At the end of this exercise you shall be able to
• ream through holes within limits and check reamed holes with cylindrical pins.

Determining the drill size for reaming
Use the formula,
drill diameter = reamed hole size. (undersize + oversize)

Refer to the table for the recommended undersizes in related Theory on DRILL SIZES FOR REAMING.
Hand reaming
Drill holes for reaming as per the sizes determined.

Note: Place the work on parallels while setting on the machine vice. (Fig 1)

Fig 1

Chamfer the hole ends slightly. This removes burrs, and will also help to align the reamer vertically (Fig 2). Fix the
work in the bench vice. Use vice clamps to protect the finished surfaces. Ensure that the job is horizontal.

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CITS : C G & M - Fitter - Exercise 62