Page 101 - CITS - Fitter Trade Pactical - Volume - 2

FITTER - CITS

EXERCISE 30: Exercise on tapping through and blind holes

to suit stud & bolt

Objectives

At the end of this exercise you shall be able to
• determine the hole size for tapping
• chamfer the holes for tapping
• set the tap in the hole
• set the height for blind hole
• drilling blind hole
• cut internal threads in through and blind holes using hand tap and tap wrench.

Job Sequence

Cut internal thread in through hole

• Use old finished job for this excercise.
• Make throughout hole (8.5mm dia) for making M10 thread.
• Fix the job in bench vice.
• Fix M 10 first tap in tap wrench and cut internal thread in through hole.
• Similarly, fix M 10 second tap and third tap in tap wrench one by one and cut the internal thread to form full
thread.
• Repeat the above process to cut internal thread in other drilled through hole.
Cut internal thread in blind hole
• Remove metal chips if any from the blind hole by turning it upside down and slightly tapping it on a wooden
surface.

86