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Full text of "Modern Mechanical Engineering Vol-I"

ESSENTIAL  MACHINES

101

effected by fitting strips of the required thickness round the curves, leaving
spaces between the strips about equal to their width to be occupied with
sand.

Fig. 84 is a group of various pipe patterns, two of which on the left
are skeleton structures.    The cylindrical portions are represented by discs,

Fig. 84.óGroup of Pipe Patterns, including Skeleton Structures

leaving spaces between, which are filled with sand at the time of mould-
ing. The core prints are treated in the same way. The method is only
used for work of fair dimensions, and the larger the patterns are the
greater is the economy. These examples are by Messrs. Ernest M. Brown
&Co.

CHAPTER  III
Essential Machines
It is necessary to use the qualifying adjective, because some machines that
are absolutely essential in some shops would be like white elephants in others,
where they would be only partially employed. The larger the number of
hands, and the more varied the kinds of work done, the more extensive is the
selection of machines. Small shops handling specialities cannot afford to
neglect the facilities that special machines offer. There is a wealth of labour-
saving machinery now available, much of which is of comparatively recent
growth, notwithstanding that pattern-work is still mainly that of the handi-
craftsman.