Workshop Technology
Tandem drawing of wires and tubes is necessary because

Surface finish improves after every drawing stage
It is not possible to reduce at one stage
Annealing is needed between stages
Accuracy in dimensions is not possible otherwise

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Workshop Technology
Swab is used for

Cleaning the moulding sand
Reinforcement of sand in the top part of the moulding box
Smoothing and cleaning out depressions in the mould
Moistening the sand around the edge before removing pattern

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Workshop Technology
During hot working of metals

Porosity of the metal is largely eliminated
Grain structure of the metal is refined
All of the listed here
Mechanical properties are improved due to refinement of grains

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