MOULDING IN GREEN SAND on, the cope is rammed first on a dummy sand face. A level bed is corresponding with the mould joint, the various pattern pieces are 117 swept, set on Fig. 4.—Half Fly-wheel Mould made without Pattern, using a Sweep Piece and Cores this by measurement, the cope is rammed over them and removed, the sand in the bed dug out, the mould made, and finally covered with the cope, which is guided into its original posi- tion with the stakes. Though these large moulds are made in green sand, the surfaces are often hardened slightly by the process of " skin-drying". A devil containing burning charcoal or coke is suspended in the mould, which drives off a portion of the moisture. But for dried moulds, a different mixture of sands is necessary, and these are con- tained wholly in boxes. Figs. 4 to 9 illustrate ex- amples of work made in the floor. Fig. 4 is a half fly- wheel mould. The rim has been formed with a sweeped piece, and the arms with cores. The joint faces of the rim and the boss are closed with pieces of loam cake. Fig. 5 is a portion of a fly-wheel. Fig. 5.—Portion of Fly-wheel Mould A, Half cores closed. B, Half core open.