Page 105 - CITS - Fitter Trade Pactical - Volume - 2

FITTER - CITS

Internal threading blind holes using hand taps

Objectives: At the end of this exercise you shall be able to
• practice Internal threading blind holes using hand taps.

Drilling a blind hole

Determine the tapping drill size using the table for tapping drill sizes.
Drill a blind hole using the depth stop arrangement. The depth of the tapping hole should be slightly more than the
depth of the required thread. (Fig 1)

Fig 1

Procedure for threading
Remove metal chips, if any, from the blind hole by turning it upside down and slightly tapping it on a wooden
surface.

Do not clear the chips by blowing as it can cause injury to your eyes.

Screw a matching nut on the first tap to act as a depth stop. (Fig 2)

Thread the blind hole until the nut touches the plate surface.
Remove the chips from the hole frequently, using a flattened and bend wire. (Fig 3)

Fig 2 Fig 3

90

CITS : CG & M - Fitter - Exercise 30