The moulding of fly-wheels may be done either with or without patterns. In case a pattern is used the work is done as already indicated for ordinary work. Where no pattern is used the sweep again comes into play. In this case, however, the outside face of the mould as well as the bed is swept. This leaves a cylindrical pit with a diameter equal to that of the wheel to be made and a depth equal to the face of the rim. The cores for the spokes are placed exactly as already described for gear wheels.
Large wheels are usually made in sections. This is done to avoid the dangers of internal stresses and the resultant cracking due to cooling. These sections may be cast from a pattern or swept sis desired.
Pipes are usually moulded on the side with a dry sand core as already described for columns. It is customary, however, in many foundries to turn the mould on end for pouring. When this is done a riser is located at the upper end into which the impurities of the iron and the washings from the core may rise as a scum. This insures a sounder casting than when cast on its side. All cast iron pipes that are to be subjected to an internal or external pressure should be cast on end.