Drawing format is the systematic space arrangement of required information within the drafting sheet. This information is used to identify, process, and file drawings methodicaly. Standard sizes and formats for military drawings are arranged according to DoD-STD-100C, Engineering Drawing Practices, and MIL-HDBK-1006/1, DoD-STD-100C and MIL-HDBK-1006/1 are your guidelines for preparing SEABEE drawings. Most of the documents applicable to these standards have recently been revised and updated in order to gain like information and to share uniformity of form and language within the Naval Construction Force and between DoD organizations. Other influencing factors are the current widespread use of reduced-size copies of both conventional and computer-generated drawings and exchange of microfilm.

Standard drawing sheet sizes are used to facilitate readability, reproduction, handling, and uniform filing. Blueprints produced from standard size drawing sheets are easily assembled in sets for project stick files and can readily be folded for mailing and neatly filed in project letter size or legal size folders. (Filing drawings and folding blueprints will be covered later in this training manual.)

Finished format sizes for drawings shown in figure 3-14, view A, are according to ANSI Y14.1

Figure 3-14.-Guide for preparing horizontal and vertical margins, sizes, and finished drawing format.

(1980), approved and adopted for use under DoD-STD-100C. Flat size refers to drawings that, because of their relatively small size, should be stored or filed flat. Roll size refers to drawings that, because of their lengths, are filed in rolls. Finished format sizes for a drawing refer to the dimensions between trim lines (X and Y in figure 3-14, view A). The TRIM LINE is the outside line of either the vertical or horizontal margin. The inside lines of the margins are called BORDERLINES. Width (X) is always PARALLEL to the working edge of the drawing board; length (Y) is always PERPENDICULAR to the working edge of the drawing board. Notice, in figure 3-14, view B, that 2 in. should be added to the left margin and to the right margin for protection of roll-size drawings. The edge of a drawing prepared on tracing paper will tear easily after it is rolled and unrolled several times.

Sheets of drafting or tracing paper are cut slightly larger than their required finished sizes and are fastened to the drafting board as previously described. Using a hard (4H to 6H) pencil and a T square (or parallel straightedge), draw a horizontal trim line near the lower edge of the paper. Then draw a vertical trim line near the left edge of the paper with a T square (or parallel straightedge), pencil, and triangle, as previously described. Dimensions establishing the finished length of the sheet (distance between vertical trim lines) and the location of the vertical borderlines are marked off on the horizontal trim lines. A full-size scale should be used when you are laying off a series of measurements along a line. Dimensions establishing the finished width of the sheet (distance between horizontal trim

Figure 3-15.-Preparing title block for A-, B-, C-, and G-size drawings.

lines) and the location of the horizontal borderlines are marked off on the vertical trim lines. Dimensions may be scaled along the borderlines.

After the drawing is completed, borderlines are given the required weight. After the completed drawing has been removed from the board, it is cut to its finished size along the trim line. If blueprints are to be made on paper that is not precut to the standard drawing size, you may find it necessary to leave an extra margin outside the trim lines. By leaving an extra margin, you can darken the trim lines. The darkened trim lines, when reproduced, will provide a visible line for trimming the blueprints to size. The extra margin will also help protect the drawing when it is repeatedly handled or attached to the drawing board later for revisions.