TLE 8 Mechanical Drafting Reviewer PDF

Department of Education Region III Division of City of San Fernando Information and Communication Technology High School Sin...

Department of Education Region III Division of City of San Fernando Information and Communication Technology High School Sindalan, City of San Fernando (P) Tel No, (045) 455-1963/e-add: [email protected] REVIEWER IN TLE 8 (MECHANICAL DRAFTING) Drafting and Drafting Tools Scenario: Maria, a first-year architecture student, has just started learning about drafting and the tools and materials required for creating precise and accurate technical drawings. She is tasked with drafting a floor plan of a small house and needs to use the appropriate materials and tools to complete the task. Below are the tools and materials Maria selects for her drafting process: o Drafting Materials: Maria starts by preparing her materials for the project: ▪ Drawing Paper: She chooses high-quality Oslo paper for her drawings because it is durable and can withstand pressure from the pencil, ensuring clean and precise lines throughout the drafting process. ▪ Masking Tape: Maria uses masking tape to secure the drawing paper onto her drawing board. This tape is easy to remove without damaging the paper or board, which ensures that her final drawing remains intact. ▪ Pencil and Eraser: Maria uses a set of different pencils for her drawing. She selects a harder pencil (H grade) for fine lines and a softer pencil (B grade) for darker, thicker lines. She also keeps a soft eraser handy to correct any smudges and a harder eraser to make more significant changes. ▪ Pencil Sharpener: Maria ensures her pencils are always sharp using a reliable pencil sharpener, as dull pencils can affect the precision of her lines. o Drafting Instruments: To ensure accuracy, Maria selects the appropriate drafting instruments: ▪ T-Square: Maria uses the T-square to draw the horizontal lines of the floor plan. It helps guide the triangles and keeps the lines perfectly straight. ▪ Triangle: She uses a 30x60-degree triangle to draw accurate vertical lines and other angled lines for the floor plan. She ensures the triangle is securely placed against the T-square to avoid mistakes. ▪ Compass: Maria uses the compass to draw precise circular arcs for rounded corners of the house or any circular features such as windows or doors. ▪ Protractor: She uses the protractor to measure and draw angles, especially for sections of the floor plan where non-90- degree angles are required. ▪ Divider: When Maria needs to divide a line or arc into equal sections, she uses the divider to measure precise distances and mark them for accurate spacing on her drawing. o Using the Drafting Tools: Maria begins the drawing process: ▪ She secures the drawing paper using masking tape, ensuring the edges are aligned. ▪ She starts with the basic layout, using the T-square and triangle to draw horizontal and vertical lines for the main structure of the house. ▪ For accurate measurements and scaling, she uses a triangular scale to reproduce the dimensions of the house at a reduced size. ▪ She employs the compass to add curved features, such as a circular driveway or rounded doorways. ▪ To ensure precise angles, she measures the angles using a protractor and uses the divider to divide lines into equal parts for consistent spacing in the design. Final Steps: o Once the initial drawing is complete, Maria reviews her work for any mistakes. She uses the eraser to clean up any unwanted marks and corrections made with the pencil. o As a final touch, she ensures all lines are clearly defined and that the dimensions on the drawing are properly scaled and accurate. Key Takeaways: Drafting Materials: Maria carefully selects materials such as drawing paper, masking tape, pencils, and erasers to ensure a smooth and precise drafting process. Drafting Instruments: She uses specialized tools like the T-square, triangle, compass, protractor, and divider for accurate measurements, angles, and shapes. Drafting Process: By utilizing the correct materials and tools, Maria is able to create a detailed and accurate floor plan, ensuring her design is well-organized and easy to modify if necessary. CONVERTING INCHES TO CENTIMETERS Formula for Conversion: To convert inches to centimeters, you can use the following conversion factor: 1 inch=2.54 centimeters1 \, \text{inch} = 2.54 \, \text{centimeters}1inch=2.54centimeters Thus, to convert inches to centimeters, multiply the number of inches by 2.54. Steps for Conversion: Identify the number of inches you want to convert. Multiply the number of inches by 2.54 (since 1 inch equals 2.54 cm). Write the result as the number of centimeters. TWO SYSTEMS OF MEASUREMENT English system ❑ Originated in ENGLAND ❑ The basic units for length or distance measurements in the English system are the inch, foot, yard, and mile. Metric System or SI UNIT ❑ Originated in FRANCE ❑ The metric system is a system of measurement that uses the meter, liter, and gram as base units of length (distance), capacity (volume), and weight (mass) respectively.   Industry standard classifying the different types of lines used in drawings.  Developed by the American Society of Mechanical Engineers (ASME).  Lines are classified by line thickness and drawn thin or thick.  Thick lines are typically drawn with a 0.7 mm or 0.9 mm mechanical pencil.  Thin lines are typically drawn with a 0.3 mm or 0.5 mm mechanical pencil. ALPHABET OF LINES 1. OBJECT OR VISIBLE LINES – Thick dark line use to show outline of object, visible edges and surfaces. 2. CONSTRUCTION LINE – Very light and thin line use to construct layout work. 3. DIMENSION LINE – Thin and dark lines use to show the size (span) of an object with a numeric value. Usually terminates with arrowheads or tick markings. 4. HIDDEN LINE – Short dash lines use to show non visible surfaces. Usually shows as medium thickness. 5. CENTER LINE – Long and short dash lines. Usually indicates center of holes, circles and arcs. Line is thin and dark. 6. EXTENSION LINE – Thin and dark line use to show the starting and ending of dimension. 7. CUTTING PLANE LINE – Extra thick lines use to show cutaway views or plane of projection where a section view is taken. Arrow indicates the direction of view. 8. SHORT AND LONG BREAK LINES –Short and long medium line use to show cutaway view of a long section. 9. LEADER LINE – Medium line with arrowhead to show notes or label for size or special information about a feature. 10. PHANTOM LINE – Long line followed by two short dashes use to show alternate position of a moving part. 11. SECTION LINE – Medium lines drawn at 45 degrees use to show interior view of solid areas of cutting plane line. Drafting as a Language  Drafting is called a “universal language”  Symbols (lines and figures) have specific meaning are used.  The symbols accurately describe the shape, size, material, finish, and fabrication or assembly of a product.  Drafting is also known as the “language of industry”  Industry uses this precise language because the drawings must communicate the information the designer had in mind to those who produce the product. ORTHOGRAPHIC PROJECTION ❑ A system for graphical representation of an object by a line drawing on a flat surface. ❑ A parallel projection technique in which the plane of projection is perpendicular to the parallel line of sight. ORTHOGRAPHIC VIEW a drawing that shows a side of an object viewed directly from 90 degrees. MULTIVIEW DRAWING a drawing that shows more than one view of an object. Multiview Projection The system of views is called multiview projection. Each view provides certain definite information.  All three-dimensional objects have width, height, and depth. Width is associated with an object’s side to-side dimension. Height is the measure of an object from top-to-bottom. Depth is associated with front-to-back distance. KEY CHARACTERISTIC OF DRAFTING Drafters must be able to turn plans and ideas into technical drawings of buildings, tools, and systems. Detail oriented. Drafters must take care that the plans they convert are technically accurate according to the outlined specifications. Reviewer: Gothic and Roman Lettering Techniques Technical Lettering is essential in engineering and architectural drawings as it provides important information such as measurements, guidelines, and notes. The main purpose of technical lettering is to make the writing clear, legible, and consistent, ensuring the details in the drawing are easily understood. What is Lettering? Lettering is the process of writing alphabets (A-Z) and numerals (0-9). It is a vital skill for creating clear and professional technical drawings. The quality of lettering impacts the readability and overall presentation of your design. Classification of Lettering Lettering is generally divided into two categories: 1. Gothic Lettering 2. Roman Lettering Gothic Lettering Gothic lettering is characterized by bold, angular shapes and is widely used in mechanical drafting. It conveys a sense of strength and precision, making it ideal for technical drawings where clarity and structure are important. Single Stroke Vertical Gothic Lettering: These letters are vertical with a consistent thickness throughout, made with a single stroke, similar to the thickness of a pencil line. Single Stroke Inclined Gothic Lettering: These letters are also made with a single stroke but are inclined at an angle of 75° to the horizontal line. Double Stroke Vertical Gothic Lettering: These letters are drawn with two strokes of the pencil, giving them a thicker, more defined appearance, but the strokes are uniform in thickness. Roman Lettering Roman lettering is known for its elegance and simplicity, and it is widely used in architectural drawings. It is favored for its readability and balanced design, which makes it easy to understand at a glance. Roman Lettering: This style uses a combination of thick and thin elements to form the letters. The contrast between the thick and thin lines is what gives Roman lettering its distinctive, classic look.  Roman lettering is often used where clarity and legibility are essential, such as for labels, titles, and notes in technical and architectural drawings. Freehand Lettering Freehand lettering refers to writing alphabets without the use of any drawing instruments. It requires a steady hand and consistent size for legibility. While freehand lettering is less precise than other types, it is still useful in situations where speed and flexibility are needed. Summary of Key Points: Gothic Lettering: Bold and angular, used in mechanical drafting. There are single stroke vertical, inclined, and double stroke variations. Roman Lettering: Elegant and clear, used in architectural and technical drawings. It emphasizes line thickness and balance. Freehand Lettering: Writing without instruments, requiring a steady hand for legibility. Tips for Effective Lettering: Consistent Size: Ensure all letters and numbers are the same size for clarity. Proper Spacing: Space the letters evenly to avoid clutter. Clear Lines: Whether you're using gothic or roman lettering, the lines should be clean and uniform to ensure readability. By mastering these lettering techniques, you'll be able to create precise and professional-looking technical drawings.