of loose sand
over the surface for a good bearing. Place another cover board on
top, as shown at D, and by grasping with both hands, as shown,
turn the drag other side up. Remove the upper cover board and
place the upper half of the flask, or "cope," in position, as
shown at E.
In order to prevent the two layers of sand sticking together, the
surface of the sand at E should be covered with coal-dust. This is
done by shaking the coal-dust bag over the flask, after which the
dust on the pattern may be removed by blowing. The cope is then
filled with sand and rammed in exactly the same manner as in the
case of the drag.
After the ramming is done a number of vent holes are made, as
shown at F, from the surface of the mold to the pattern, in order
to allow the escape of air and steam when the mold is being
poured. These vent holes may be made by pushing a wire about the
size of a knitting-needle down through the sand until it touches
the pattern. The "sprue," or pouring-hole, is next cut, by means
of the sprue-cutter shown at the right, which consists of a piece
of thin brass or steel tubing about 3/4 in.
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