The second method is less common an

The second method is less common and is similar to Method 1 in that it too lists out Assemblies, Parts, and Standard Parts/Purchased Components. The exception arises in that the “MATERIAL” and “STANDARD NO. / VENDOR NO. / MATERIAL SIZE” Columns, a detail part would contain a material standard, stock dimensions and a cut length. These detail parts would be items that are so simple in design that either (1) they require no detail views describing how to manufacture the detail part or (2) views of the assembly DWG allow the detail part to be fully dimensioned and therefore don’t require a separate detail DWG sheet to manufacture the item. In other words, the detail part could be cut to length directly from the BOM callout or by referencing the main views or detail views of the shown assembly. Method 2 would be applicable to say a weldment (assembly) drawing. As shown in the example below, “MATERIAL SIZE” Column callout could be used to make a rectangular plate, a rolled or extruded structural shape (I-beam. Wide Flange, Angle Channel), Hollow Box Section or Tube, etc. If the detail part was heat treated, then the detail part would have a hardness callout in the “HEAT TREAT” cell of the BOM.