Draft allowance-

A taper of 0.01 to 0.025mm/mm is generally provided on the vertical faces of the patterns for its easy withdrawl from the mould. The taper is called the draft allowance.

Shrinkage allowance-

Shrinkage allowance is provided to compensate for contraction of the casting when the temperature of the solidifying metal in the mould cavity drops from freezing to room temperature. Shrinkage allowance is generally in the range of 0.01 to 0.016mm/mm, depending upon the type of material.