When an error is discovered on a drawing while in use in the shop, quite often the error will be marked with a red or yellow pencil. Any such error is usually reported to the supervisor so that corrections can be made on future drawings or on the master drawing of the print being used. […]

It is possible that lines representing two different surfaces of an object shown in one view would, when shown in another view, appear as one line. This tends to make the drawing confusing and more difficult to read. Therefore, one of these lines may be shown out of true projection in order to show the […]

When an object is shown in true projection, it is drawn in all views as it actually appears. However, in some cases, one view of the object may be shown as it does not actually appear. For example, in a revolved view, a portion of the object is rotated in order to obtain a straight […]

While prints may be drawn to a reduced, full, or enlarged scale size, parts are often shown in an enlarged scale. The enlarged portion of the part, also called the enlarged detail, is shown as an additional view usually located near the principal view to which it applies, Figure 7.9. The enlarged detail provides more […]

The preceding units showed that six basic views can be used to represent an object: front, top, right side, left side, bottom, and back. The proper selection and arrangement of several of these views are usually suf­ficient to represent an object. However, when an object has a slanted (oblique) face, an auxiliary view may be […]

VIEWS WITH CONVENTIONAL BREAKS FIGURE 7.1 ■ Typical conventional break symbols. Many of the structural shapes to be drawn are too long to be shown on a print in their true size. In addition, the use of a reduced scale size would be impractical because it would be dif­ficult to show fine details. However, this […]

The following is an overview of structural metal shapes commonly used in the fabrication of weldments. Figure 6.2 and Figure 6.3 show these shapes. Table 6.2 describes how size specifications are given for com­mon shapes. When ordering structural metal, reference is made to manufacturers’ catalogs. These catalogs contain tables with a listing of the sizes […]

There are many types and styles of structural metal shapes used in the welding industry. Most weldments use combinations of these shapes. In reading prints, it is essential to know the shapes available and how their sizes are specified. The Appendix contains size specifications of common structural shapes. As discussed in Unit 5, sheet metal […]

When it is necessary to specify a particular type of steel in a bill of material, it is often identified by an AISI (American Iron and Steel Institute)-SAE (Society of Automotive Engineers) classification number. AISI-SAE refers to a standard numbering system for designating carbon and alloy steels. This system essen­tially indicates the nominal composition of […]

PREPARATION OF A BILL OF MATERIALS The designer/drafter is usually required to prepare a list or bill of materials along with weldment drawings. This list enables some other person, such as a stockroom attendant, a welder’s helper, or the operator of flame — cutting equipment, to cut or otherwise prepare the various stock pieces needed […]