Modern Mechanical Engineering Vol-I

i

':!

76

PATTERN-MAKING

number from twenty to thirty, depending on the design. These are almost
invariably rammed in iron boxes to ensure permanence of form, and their
positions in the mould are tested carefully by means of metal gauges.

Fig. 42 shows a plain cylinder pattern
for a motor-cycle, by Messrs. Ernest M.
Brown & Co. of Huddersfield. One-
half the core box is seen at the right.
The relation of the core to the pattern
and its prints can be observed in the
half pattern open in the joint face to
the left. There the thickness of metal
is painted black, a practice which is
commonly adopted in cored work, since
it is of assistance to the moulder when
inserting the cores. A cover is seen at
the left of the figure.

Fig. 43 shows the method of lagging,
with other details for a small compound
engine, in which the high- and low-
pressure cylinders were cast together with

T« 43-—Pattern for Compound Cylinder

Fig. 44.—Pattern of Diesel Engine Cylinder
and Base