Difference Between Fin and Swell

         Swell : The unintentional bulges found on the casting surfaces are known as swells. Such enlargements on the casting surface are caused by the liquid metal pressure which succeeds in pushing back the mould sand at certain places. This additional space is occupied by the molten metal and this results in the enlargement of casting.

        Fin : This is unwanted metal on the casting which remains on it after separate out the casting from the mould. The operation of removal of these unwanted metal parts attached to the casting is called snagging. The common methods used for their removal are the following :

        1. Chipping with hand or pneumatic chisels.

        2. Cutting with an oxy-acetylene flame.

        3. Grinding by means of a pedestal, bench, portable or swing frame grinder.    

        4. Machining.