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Full text of "Modern Mechanical Engineering Vol-I"

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.