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Full text of "Modern Mechanical Engineering Vol-I"

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portions for cleaning and coring.   Many beds of large dimensions are made
without full patterns from motives of economy.     The exterior mould is

Fig. 68.—Formation of Curved

Fig. 69.—Method of making a Curved Corner

made from a skeleton frame, aided with strickles or sweeping boards, and
cores impart the shapes to the interior portions. In all long and narrow
beds, solid-plated on one face only, the effect of unequal shrinkage is to

Fig. 72
Methods of Blocking adopted for Curves

cause curving or camber, the solid-plated portion when cold becoming
concave lengthwise to the extent of from J in. to | in., depending on the
length. The pattern must be curved in the opposite direction to neutralize
this effect.