Page 121 - CITS - Fitter Trade Practical - Volume -2

FITTER - CITS

Procedure Slip pack Calculation

a First write the required dimension 44.8725
1.0005 substract 1.0005
b Select the slip gauge having the 4 decimal place
th
43.872
c Select 1 series slip that has the same last figure 1.002 substract 1.002
st
42.870
1.37 substract 1.37
d Select the 2 series slip that has the same last fig-
st
ure and that will leave 0.0 or 0.5 as the last figure 41.5
e Select a 3 series slip that will leave the nearest 16.5 substract 16.5
rd
4 th series slip
16.5
(41.5 - 25 = 16.5) 25.00
f Select a slip that eliminates the final figure Add
25.0 substract 25.00
Total pieces 44.8725 00.00

Maintenance of measuring instruments

Objectives : At the end of this exercise you shall be able to
• state the preventive measures to be taken for protecting precision measuring instruments.

Precision measuring instruments play an important role in maintaining the quality of the products. Measuring
instruments are also very expensive. It is important that the instruments are well looked after and maintained by
the person who uses it.
Protection against corrosion
High atmospheric humidity and sweat from hands can cause corrosion to instruments. Avoid this.

Acid-free vaseline (petroleum jelly) applied lightly on the instruments can give protection against corrosion.
(Fig 1)

Fig 1

Be sure that the instruments are thoroughly cleaned and free from water or moisture before applying vaseline.
Use chamois leather for giving a light coating of vaseline.
Always clean the slip gauges with carbon tetrachloride and apply petroleum jelly after use.

Remove burrs and metal particles. Burrs on workpieces can cause scratches and damages to measuring equip-
ment. They can also damage other workpieces.

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CITS : C G & M - Fitter - Exercise 77