178 Chapter 7
ings, an assembly drawing provides the information the print reader needs to assemble the components.
The bill of materials (BOM), which is basically a tabulated list, may be placed either on the assembly
drawing or on a separate sheet. The list gives critical information such as part numbers, names, quan-
tities, material detail-drawing number, and sometimes stock sizes of raw material, etc. The term “bill of
materials” is usually used in structural and architectural drawing, whereas the term “part list” is used in
machine-drawing practice.
A three-dimensional picture of a complete assembled unit facilitates the reader’s ability to visualize
the final shape of the assembly (Figure 7.15). Front, side, and top views may be necessary to commu-
nicate dimensions or shapes to the reader. If this assembly drawing is actually one of several subassem-
bly drawings, the print should indicate this in the title block or the BOM.
Likewise, a maintenance technician would normally need assembly drawings at the work site to
evaluate the best sequence for the dismantling of specific machinery, to locate parts that must be ac-
Figure 7.14A An exploded assembly drawing typical of drawings found in machinery catalogs showing the
various components laid out in their correct order of assembly (source: StoneAge, Inc.).