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CHAPTER 3 DRAFTING: FUNDAMENTALS AND TECHNIQUES; REPRODUCTION PROCESS In this chapter you will learn the fundamental and basic techniques associated with the use of drafting equipment and accessories commonly used by the EA in preparing drawings and charts. The techniques are applied using standard drawing format, line conventions, and lettering described in detail in two of the publications you will use most often:DoD-STD-100C, Engineering Drawing Practices, and MIL-HDBK-1006/1, and other applicable reference materials to ensure that your drawings are prepared according to the latest revisions. This chapter also covers the procedures related to the safe use and maintenance of the typical reproduction equipment and discusses the different methods of reproducing drawings and the types of drawing paper used. This training manual will not cover specific reproduction responsibilities since each command may have different reproduction equipment depending on its mission and the size of its engineering department. When you are assigned this responsibility, you will be given additional on-the-job training. WORK PREPARATION Before you begin to work, you should devote some time and thought to organizing your working area. Drafting furniture should be arranged so you can work comfortable y without fatigue or eyestrain. Be sure to check the lighting before you set up your drafting table. You can devise a system of stowing your equipment and supplies so that they are handy and in order.WORK AREA Your immediate work area should be large enough to allow sufficient freedom of movement, but not so large that you waste time reaching for equipment, supplies, and reference publications. An ideal working area allows each draftsman approximately 90 sq ft of space, although you may actually have more or less depending on the total area of the drafting room and the number of draftsmen who will work there.If you are easily distracted, do not butt your drafting table up against and facing another draftsmans table. Ensure that you have adequate lighting. The best light for drafting is natural light coming over the left shoulder and from the front left to avoid shadows cast by your hands, T square or parallel ruling straightedge, and triangles. Avoid a glaring light as it will cause eyestrain. Use the drafting lamp that was described in chapter 2. Your drafting table height should be from 36 to 40 in. above floor level. Your drafting chair or stool should be high enough that you can see the whole drawing board, but not so high that you have to lean over uncomfortably to draw. As mentioned in chapter 2, the board may be inclined or left flat according to your preference. A slope of 1 to 8 works well for the inclined position. By shifting your body or head slightly, you should be able to look directly at any point on an average-sized drawing sheet; that is, your line of sight should be approximately perpendicular to the drawing surface.Before you begin to draw, arrange your equipment in an orderly manner. Place each article so that you can reach it easily, and keep it in place when you are not using it. A systematic arrangement is timesaving and efficient. You decrease the likelihood of accidentally dropping your tools or pushing them off the table if you keep them in order. You will find it very convenient to have a small worktable adjacent to your drafting board. Placing your drafting tools and reference publications on the worktable leaves you with an uncluttered drawing board surface. When you use the drafting board in the inclined position, a separate worktable becomes a necessity.YOUR EQUIPMENT AND MATERIALS Selection of drafting equipment and materials will depend largely upon each of your drafting assignments. Let your good judgment and common sense guide you in their selection. After some experience, you will automatically select proper equipment and materials as they are required. Until you become proficient, dont hesitate to seek the advice of your drafting supervisor or an experienced draftsman. Assign-ments to staff and support billets within the Naval Construction Force (NCF) will expose you to modern drafting equipment and materials, such as the adjustable drafting board with a drafting machine attached.Drafting Board As a SEABEE draftsman, you will probably not be able to select your drafting board. Unless the board is new, it will probably be marred and full of small pinholes. To obtain a smooth drawing surface, you should cover the board with a vinyl material or heavy manila paper. Laminated vinyl covering minimizes pencil scoring, is non-glaring, and is easily kept clean by wiping with a damp cloth. Heavy manila paper will serve the same purpose, but must be replaced when it becomes soiled or marked with use. |
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