Materials Numerical Quantities-Forms Tables compiled for the metal trade are dedicated to vocational schools as well as to practical usage at the job site. Although the tables have been compiled for use primarily by the apprentice, the specialized worker will also find them useful. Every effort has been made to shorten the sometimes tedious operations and the arrangement of subject matter is such that its contents are readily available to the practical man.

Much painstaking effort must go in compiling and arranging such tables. Information must be so selected that the reader can, from the bulk of material, easily find out the subject of his interest. Often, a decision of either selecting an item or rejecting it proves difficult. Too much material packed into tabular compilations can be as harmful as the omission of some vital pieces of information.

Not only the selection but also the arrangement of material requires considerable thought if the contents of the tabular compilations have to be offered for ready reference. Only then can the reader decide where to look for proper information. The principle of order must be evident at once.