Page 110 - CITS - Fitter Trade Pactical - Volume - 2
P. 110

FITTER - CITS






             Fig 3                                       Fig 4
















           Reaming drilled holes using hand reamers


           Objectives : At the end of this exercise you shall be able to
           •  state Reaming drilled holes using hand reamers.


           Reaming drilled holes using hand reamers
           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.

              Place the work on parallels while setting on the machine vice. (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.


              Fig 1                                       Fig 2


















           Fix the tap wrench on the square end and place the reamer vertically in the hole. Check the alignment with a try
           square. Make corrections, if necessary. Turn the tap wrench in a clockwise direction applying a slight downward
           pressure at the same time (Fig 3). Apply pressure evenly at both ends of the tap wrench.
           Apply cutting fluid.
           Turn the tap wrench steadily and slowly, maintaining the downward pressure.

              Do not turn in the reverse direction it will  scratch the reamed hole. (Fig 4)



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 CITS : CG & M - Fitter - Exercise 31       CITS : CG & M - Fitter - Exercise 31
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