Modern Mechanical Engineering Vol-I

*3<S FOUNDRY WORK

until the top of the box is reached. The vent wire is now used freely, being
driven from the central open space to the box sides. The interior is next
filled with broken cinders or clinkers just lightly consolidated with the
rammer, a piece of tube inserted to receive and convey away the vents, and
the core is completed with sand rammed over the cinders to the top of the
box. The edges are swabbed with water, the box sides detached and removed,
leaving tne core standing ready to be put into the drying stove.

g, 45.—"Jetting a Core diagonally with
bottom, and top prints

Fig. 46.—Pattern with a long top print
for fig. 45

Referring to fig. 15, it will be noticed that the ratchet cast on one end is
shrouded or capped, which involves making a joint in the core. The box
is shown in fig. 32, the ring core being in halves for insertion in top and
bottom moulds, the core for the ratchet in fig. 33, and the remainder in fig. 34.
Fig. 35 shows the core box for a bevel wheel, with the core completed,
the grid, and central mass of cinders being indicated, and the strickle that
produces the curve corresponding with the edges of the vertical arms. Fig.
36 illustrates the mould, cored and closed for pouring.
Cores that are curved and thin, like those for the passages of cylinders,
have to be stiffened with rods, and vented with channels. Fig. 37 shows
a core box, ready for ramming, with vent rods inserted; fig. 38 a core with
stiffening rods; fig. 39 shows vent rods in a core previous to its removal from
the box; and fig. 40 the filing of grooves where the rods cross, for the
insertion of core strings, the portion filed being filled after, and the string
withdrawn.
Fig, 41 illustrates the fitting of cores in drop print impressions; fig 42,
the thrusting of a core along into a boss, the space behind to be filled with
sand; fig. 43, the inclusion of two cores made in one box, with drop prints
common to both; figs. 44 to 46, two methods of setting round cores diagonally.