Normal shrinkage allowance for aluminium is 18 mm per metre and that for cast iron 10 mm per metrD. If the metal pattern is to be made of aluminium and the casting is to be of cast iron, the shrinkage allowed on wooden master pattern will be
A)10 mm/metre
B)28 mm/metre
C)8 mm/metre
D)18 mm/metre

Question

Quizplus · Accepted Answer

The shrinkage allowance for the wooden master pattern combines the shrinkage of aluminium (18 mm per metre) and cast iron (10 mm per metre), totaling 28 mm per metre. This accounts for the aluminium pattern shrinking first and then the cast iron casting shrinking from the size of the aluminium pattern.

Normal Shrinkage Allowance for Aluminium Is 18 Mm Per Metre