APPENDIX I GLOSSARY

When you enter a new occupation, you must learn the vocabulary of the trade in order to understand your fellow workers and to make yourself understood by them. Shipboard life requires that Navy personnel learn a relatively new vocabulary. The reasons for this need are many, but most of them boil down to convenience and safety. Under certain circumstances, a word or a few words mean an exact thing or a certain sequence of actions, making it unnecessary to give a lot of explanatory details. A great deal of the work of a technician is such that an incorrectly interpreted instruction could cause confusion, breakage of machinery, or even loss of life. Avoid this confusion and its attendant danger by learning the meaning of terms common to drafting. This glossary is not all-inclusive, but it does contain many terms that every craftsman should know. The terms given in this glossary may have more than one definition; only those definitions as related to drafting are given.

ALIGNED SECTION-A section view in which some internal features are revolved into or out of the plane of the view.

ANALOG-The processing of data by continuously variable values.

ANGLE -A figure formed by two lines or planes extending from, or diverging at, the same point.

APPLICATION BLOCK -A part of a drawing of a subassembly showing the reference number for the drawing of the assembly or adjacent subassembly. ARC-A portion of the circumference of a circle.

ARCHITECT'S SCALE-The scale used when dimensions or measurements are to be expressed in feet and inches.

AUXILIARY VIEW             An additional plane of an object, drawn as if viewed from a different location. It is used to show features not visible in the normal projections.

AXIS-The center line running lengthwise through a screw.

AXONOMETRIC PROJECTION -A set of three or more views in which the object appears to be rotated at an angle, so that more than one side is seen

BEND ALLOWANCE An additional amount of metal used in a bend in metal fabrication.

BILL OF MATERIAL-A list of standard parts or raw materials needed to fabricate an item.

BISECT-To divide into two equal parts.

BLOCK DIAGRAM-A diagram in which the major components of a piece of equipment or a system are represented by squares, rectangles, or other geometric figures, and the normal order of progression of a signal or current flow is represented by lines.

BLUEPRINTS -Copies of mechanical or other types of technical drawings. Although blueprints used to be blue, modem reproduction techniques now permit printing of black-on-white as well as colors.

BODY PLAN-An end view of a ship's hull, composed of superimposed frame lines.

BORDER LINES-Darklines defining the inside edge of the margin on a drawing.

BREAK LINES-Lines to reduce the graphic size of an object, generally to conserve paper space. There are two types: the long, thin ruled line with freehand zigzag and the short, thick wavy freehand line.

BROKEN OUT SECTION-Similar to a half section; used when a partial view of an internal feature is sufficient.

BUTTOCK LINE-The outline of a vertical, longitudinal section of a ship's hull.

CABINET DRAWING-A type of oblique drawing in which the angled receding lines are drawn to one-half scale.

CANTILEVER -A horizontal structural member supported only by one end.

CASTING-A metal object made by pouring melted metal into a mold

CAVALIER DRAWING-A form of oblique drawing in which the receding sides are drawn full scale, but at 45 to the orthographic front view.

CENTER LINES-Lines that indicate the center of a circle, arc, or any symmetrical object; consist of alternate long and short dashes evenly spaced.

CIRCLE-A plane closed figure having every point on its circumference (perimeter) equidistant from its center.

CIRCUMFERENCE-The length of a line that forms a circle.

CLEVIS-An open-throated fitting for the end of a rod or shaft, having the ends drilled for a bolt or a pin. It provides a hinging effect for flexibility in one plane.

COLUMN-High- strength   vertical   structural members.

COMPUTER-AIDED DRAFTING (CAD) -A method by which engineering drawings may be developed on a computer.

COMPUTER-AIDED MANUFACTURING (CAM)-A method by which a computer uses a design to guide a machine that produces parts.

COMPUTER LOGIC-The electrical processes used by a computer to perform calculations and other functions.

CONE-A solid figure that tapers uniformly from a circular base to a point.

CONSTRUCTION LINES-Lightly drawn lines used in the preliminary layout of a drawing.

CORNICE-The projecting or overhanging structural section of a roof.

CREST-The surface of the thread corresponding to the major diameter of an external thread and the minor diameter of an internal thread

CUBE-Rectangular solid figure in which all six faces are square.

CUTTING PLANE LINE -A line showing where a theoretical cut has been made to produce a section view.

CYLINDER-A solid figure with two equal circular bases.

DEPTH-The distance from the root of a thread to the crest, measured perpendicularly to the axis.

DESIGNER'S WATERLINE-The intended position of the water surface against the hull.

DEVELOPMENT-The process of making a pattern from the dimensions of a drawing. Used to fabricate sheet metal objects.

DIGITAL-The processing of data by numerical or discrete units.

DIMENSION LINE-A thin unbroken line (except in the case of structural drafting) with each end terminating with an arrowhead; used to define the dimensions of an object. Dimensions are placed above the line, except in structural drawing where the line is broken and the dimension placed in the break

DRAWING NUMBER An identifying number assigned to a drawing or a series of drawings.

DRAWINGS-The original graphic design from which a blueprint may be made; also called plans.

ELECTROMECHANICAL DRAWING -A special type of drawing combining electrical symbols and mechanical drawing to show the position of equipment that combines electrical and mechanical features.

ELEMENTARY WIRING DIAGRAM (1) A shipboard wiring diagram showing how each individual conductor is connected within the various connection boxes of an electrical circuit system. (2) A schematic diagram; the term elementary wiring diagram is sometimes used interchangeably with schematic diagram, especially a simplified schematic diagram.

ELEVATION-A four-view drawing of a structure showing front, sides, and rear.

ENGINEER'S SCALE-The scale used whenever dimensions are in feet and decimal parts of a foot, or when the scale ratio is a multiple of 10.

EXPLODED VIEW-A pictorial view of a device in a state of disassembly, showing the appearance and interrelationship of parts.

EXTERNAL THREAD-A thread on the outside of a member. Example: a thread of a bolt.

FALSEWORK      Temporary supports of timber or steel sometimes required in the erection of difficult or important structures.

FILLET -A concave internal corner in a metal component, usually a casting.

FINISH MARKS-Marks used to indicate the degree of smoothness of finish to be achieved on surfaces to be machined

FOOTINGS-Weight-bearing concrete construction elements poured in place in the earth to support a structure.

FORGING-The process of shaping heated metal by hammering or other impact.

FORMAT-The general makeup or style of a drawing.

FRAME LINES-The outline of transverse plane sections of a hull.

FRENCH CURVE  An instrument used to draw smooth irregular curves.

FULL SECTION -A sectional view that passes entirely through the object.

HALF SECTION-A combination of an orthographic projection and a section view to show two halves of a symmetrical object.

HATCHING-The lines that are drawn on the internal surface of sectional views. Used to define the kind or type of material of which the sectioned surface consists.

HELIX-The curve formed on any cylinder by a straight line in a plane that is wrapped around the cylinder with a forward progression.

HIDDEN LINES    Thick,     short, dashed lines indicating the hidden features of an object being drawn.

INSCRIBED FIGURE -A figure that is completely enclosed by another figure.

INTERCONNECTION DIAGRAM -A diagram showing the cabling between electronic units, as well as how the terminals are connected

INTERNAL THREAD -A thread on the inside of a member. Example: the thread inside a nut.

ISOMETRIC DRAWING -A type of pictorial drawing. See ISOMETRIC PROJECTION.

ISOMETRIC PROJECTION-A set of three or more views of an object that appears rotated, giving the appearance of viewing the object from one corner. All lines are shown in their true length, but not all right angles are shown as such.

ISOMETRIC WIRING DIAGRAM -A diagram showing the outline of a ship, an aircraft, or other structure, and the location of equipment such as panels and connection boxes and cable runs.

JOIST-A horizontal beam used to support a ceiling.

KEY-A small wedge or rectangular piece of metal inserted in a slot or groove between a shaft and a hub to prevent slippage.

KEYSEAT-A slot or groove into which the key fits.

KEYWAY-A slot or groove within a cylindrical tube or pipe into which a key fitted into a key seat will slide.

LEAD-The distance a screw thread advances one turn, measured parallel to the axis. On a single-thread screw the lead and the pitch are identical; on a double-thread screw the lead is twice the pitch; on a triple-thread screw the lead is three times the pitch.

LEADER LINES-Two, unbroken lines used to connect numbers, references, or notes to appropriate surfaces or lines.

LEGEND-A description of any special or unusual marks, symbols, or line connections used in the drawing.

LINTEL -A            load-bearing          structural               member supported at its ends. Usually located over a door or window.

LOGIC DIAGRAM -A type of schematic diagram using special symbols to show components that perform a logic or information processing function.

MAJOR DIAMETER-The largest diameter of an internal or external thread.

MANIFOLD -A fitting that has several inlets or outlets to carry liquids or gases.

MECHANICAL DRAWING-See DRAWINGS. Applies to scale drawings of mechanical objects.

MIL-STD (military standards) -A formalized set of standards for supplies, equipment, and design work purchased by the United States Armed Forces.

NOTES   Descriptive writing on a drawing to give verbal instructions or additional information.

OBLIQUE DRAWING-A type of pictorial drawing in which one view is an orthographic projection and the views of the sides have receding lines at an angle.

OBLIQUE PROJECTION -A view produced when the projectors are at an angle to the plane the object illustrated. Vertical lines in the view may not have the same scale as horizontal lines.

OFFSET SECTION-A section view of two or more planes in an object to show features that do not lie in the same plane.

ONBOARD PLANS-See SHIP'S PLANS. ORTHOGRAPHIC PROJECTION -A        view produced when projectors are perpendicular to the plane of the object. It gives the effect of looking straight at one side.

PARTIAL SECTION-A sectional view consisting of less than a half section. Used to show the internal structure of a small portion of an object. Also known as a broken section.

PERPENDICULAR Vertical lines extending through the outlines of the hull ends and the designer's waterline.

PERSPECTIVE-The visual impression that, as parallel lines project to a greater distance, the lines move closer together.

PHANTOM VIEW -A view showing the alternate position of a movable object, using a broken line convention.

PHASE An impulse of alternating current. The number of phases depends on the generator windings. Most large generators produce a three-phase current that must be carried on at least three wires.

PICTORIAL DRAWING-A drawing that gives the real appearance of the object, showing general location, function, and appearance of parts and assemblies.

PICTORIAL WIRING DIAGRAM -A diagram showing actual pictorial sketches of the various parts of a piece of equipment and the electrical connections between the parts.

PIER-A vertical support for a building or structure, usually designed to hold substantial loads.

PITCH-The distance from a point on a screw thread to a corresponding point on the next thread, measured parallel to the axis.

PLAN VIEW-A view of an object or area as it would appear from directly above.

PLAT-A map or plan view of a lot showing principal features, boundaries, and location of structures.

POLARITY-The direction of magnetism or direction of flow of current.

PROJECTION-A technique for showing one or more sides of an object to give the impression of a drawing of a solid object.

PROJECTOR-The theoretical extended line of sight used to create a perspective or view of an object.

RAFTER -A sloping or horizontal beam used to support a roof.

RADIUS-A straight line from the center of a circle or sphere to its circumference or surface.

REFERENCE DESIGNATION -A combination of letters and numbers to identify parts on electrical and electronic drawings. The letters designate the type of part, and the numbers designate the specific part. Example: reference designator R-12 indicates the 12th resistor in a circuit.

REFERENCE NUMBERS Numbers used on a drawing to refer the reader to another drawing for more detail or other information.

REFERENCE PLANE-The normal plane that all information is referenced

REMOVED SECTION -A drawing of an object's internal cross section located near the basic drawing of the object.

REVISION BLOCK-This block is located in the upper right corner of a print. It provides a space to record any changes made to the original print.

REVOLVED SECTION -A drawing of an object's internal cross section superimposed on the basic drawing of the object.

ROOT-The surface of the thread corresponding to the minor diameter of an external thread and the major diameter of an internal thread

ROTATION-A view in which the object is apparently rotated or turned to reveal a different plane or aspect, all shown within the view.

ROUND-The rounded outside corner of a metal object.

SCALE-The relation between the measurement used on a drawing and the measurement of the object it represents. A measuring device, such as a ruler, having special graduations.

SCHEMATIC DIAGRAM-A diagram using graphic symbols to show how a circuit functions electrically.

SECTION-A view showing internal features as if the viewed object has been cut or sectioned

SECTION LINES-Thin, diagonal lines used to indicate the surface of an imaginary cut in an object.

SHEER PLAN-The profile of a ship's hull, composed of superimposed buttock lines.

SHEET STEEL-Flat steel weighing less than 5 pounds per square foot.

SHIP'S PLANS-A set of drawings of all significant construction features and equipment of a ship, as needed to operate and maintain the ship. Also called ONBOARD PLANS.

SHRINK RULE -A special rule for use by patternmakers. It has an expanded scale, rather than a true scale, to allow for shrinkage of castings.

SILL-A horizontal structural member supported by its ends.

SINGLE-LINE DIAGRAM-A diagram using single lines and graphic symbols to simplify a complex circuit or system.

SOLE PLATE-A horizontal structural member used as a base for studs or columns.

SPECIFICATION A detailed description or identification relating to quality, strength, or similar performance requirement

STATION NUMBERS         Designations of reference lines used to indicate linear positions along a component such as an air frame or ship's hull.

STEEL PLATE-Flat steel weighing more than 5 pounds per square foot.

STRETCH-OUT LINE-The base or reference line used in making a development.

STUD-A light vertical structure member, usually of wood or light structural steel, used as part of a wall and for supporting moderate loads.

SYMBOL Stylized graphical representation of commonly used component parts shown in a drawing.

TEMPER                To harden steel by heating and sudden cooling by immersion in oil, water, or other coolant.

TEMPLATE -A piece of thin material used as a true-scale guide or as a model for reproducing various shapes.

TITLE BLOCK -A blocked area in the lower right corner of the print. Provides information to identify the drawing, its subject matter, origins, scale, and other data.

TOLERANCE-The amount that a manufactured part may vary from its specified size.

TOP PLATE-A horizontal member at the top of an outer building wall; used to support a rafter.

TRACING PAPER-High-grade, white, transparent paper that takes pencil well; used when reproductions are to be made of drawings. Also known as tracing vellum.

TRIANGULATION -A technique for making developments of complex sheet metal forms using geometrical constructions to translate dimensions from the drawing to the patten.

TRUSS-A complex structural member built of upper and lower members connected by web members.

UTILITY PLAN-A floor plan of a structure showing locations of heating, electrical, plumbing and other service system components.

VIEW-A drawing of a side or plane of an object as seen from one point.

WATERLINE-The outline of a horizontal longitudinal section of a ship's hull.

WIRING (CONNECTION) DIAGRAM-A diagram showing the individual connections within a unit and the physical arrangement of the components.

ZONE NUMBERS                Numbers and letters on the border of a drawing to provide reference points to aid in indicating or locating specific points on the drawing.

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