Welcome to EdufyHUB 4U! Here, we provide easy-to-understand study materials for diploma students, especially those who face challenges with English-medium content. We want to work on complex points and make learning pleasant and uncluttered. Whether you're getting ready for tests or simply hoping to expand your knowledge, we take care of you. We should dive into the world of "Technical Drawing," a crucial subject that will help you understand and create detailed technical designs.
1. Drawing Instruments And Their Uses
Before we start it's important to have the right tools. Proper
instruments are essential for accuracy and accuracy in your drawings.
Here’s a list of the basic requirements you’ll need:
H (Light Line) or 2H (Drawing Or Writing) uses for sharper & finer lines.
Letters And Numbers (Single Stroke Vertical)
In technical drawing, lettering is essential for clearness and readability. Single stroke vertical lettering ensures consistency and accuracy. The fundamental steps to creating lettering that is neat and legible will be explained to you in this guide.
Procedure:
- Choosing the Right Pencil: Use an HB or H pencil for clarity without smudging.
- Guidelines: Lightly draw horizontal guidelines using a T-square and a set square. This helps maintain uniform height and alignment.
- Spacing: Keep consistent spacing between letters and numbers. Use the width of a single letter as a reference.
- Single Stroke Technique: Each letter and number should be drawn with a single stroke, without lifting the pencil off the paper. This technique ensures smooth and uniform lines.
Convention Of Lines And Their Applications
Understanding the basic lines used in technical drawings is crucial for creating clear and accurate diagrams. Here are the main types of lines, along with their characteristics:
Basic Lines
1. Thick Line (HB Pencil):
- Size: 0.5 mm thick.
- Use: Typically used for outlining visible edges or main objects in a drawing.
2. Medium Line (2H Pencil):
- Size: 0.3 mm thick.
- Use: Often used for dimensions, projection lines, and other medium-thickness requirements.
3. Thin Line (H Pencil):
- Size: 0.2 mm thick.
- Use: Used for finer details, like hatching, or for less prominent elements in a drawing.
4. Dotted Line:
- Style: Consists of 3 mm long dashes with 1 mm spaces between them.
- Use: Indicates hidden edges or features not directly visible.
5. Centre Line:
- Style: 3 mm dash, 1 mm space, 1 mm dot, 1 mm space.
- Use: Denotes axes of symmetry or centerlines in drawings.
5. Centre Line:
- Style: A dashed line followed by a zig-zag pattern, then dashed again.
- Use: Represents a break in an object to show the remainder is uniform or not important.
Various kinds of lines are utilized in technical drawings to convey specific meanings. Each type is explained in detail, along with their typical applications:
Types of Lines and Their Uses
1. A Type Line - Continuous Thick Line
- A1 or A2 (Outline):
- Name: Continuous thick line.
- Size: 1 mm thick.
- Use: To outline visible edges of objects (main object lines).
2. B Type Line - Continuous Thin Line
- B1 (Imaginary Line of Intersection):
- Size: 0.3 mm thick.
- Use: Represents where two surfaces intersect, but the intersection isn’t physically visible.
- B2 (Dimension Line):
- Size: 0.3 mm thick.
- Use: Used for indicating the dimensions of objects. Example: "20 mm."
- B3 (Projection Lines):
- Size: 0.3 mm thick.
- Use: Extend from an object to help draw its dimensions or align other features.
- B4 (Leader Lines):
- Size: 0.3 mm thick.
- Use: Point from a note or dimension to the feature they describe, often used in circles.
- B5 (Hatching Line):
- Size: 0.3 mm thick.
- Use: Indicates cut surfaces in section views.
- B6 (Outline Revolved Line):
- Size: 0.3 mm thick.
- Use: Shows the shape of an object rotated around an axis (e.g., round corners).
- B7 (Short Centre Lines):
- Size: 0.3 mm thick.
- Use: Mark the centers of circles or arcs.
- B8 (Thread Line):
- Size: 0.3 mm thick.
- Use: Indicates threads on screws and bolts.
- B9 (Diagonal Line):
- Size: 0.3 mm thick.
- Use: Used for shading or indicating material direction.
3. C Type Line - Free Hand Continuous Thin Line
- Size: 0.3 mm thick.
- Use: Used for drawing irregular boundaries or contours.
4. D Type Line - Continuous Thin with Zig Zag Line
- Size: 0.3 mm thick.
- Use: Represents a long break or a part removed from a drawing for clarity.
5. E Type Line - Long Chain Line
- Size: 0.3 mm thick.
- Use: Center lines, axis lines, and datum lines.
6. F Type Line - Thin Line with Small Zig-Zag
- Size: 0.3 mm thick.
- Use: Represents the long boundary line or large unbounded ends.
7. G Type Line - Long Chain Thick
- Size: 0.8 mm thick.
- Use: Additional treatment lines.
8. H Type Line - Long Chain Thick at Ends, Thin in Middle
- Size: 0.8 mm thick at ends, 0.3 mm in the middle.
- Use: Cutting plane lines or intersected plane lines.
Principal Lines and Other Lines
- Object Lines: Represent the visible edges of an object.
- Hidden Lines: Indicate edges not visible from the current view.
- Center Lines: Mark the axes of symmetry or center points.
- Cutting Plane Lines: Indicate where a section is taken.
- Dimension Lines: Show the size and spacing of features.
- Section Lines: Indicate the surfaces cut by a section view.
- Projection Lines: Extend from an object to help define its dimensions.
- Break Lines: Used to shorten the view of long objects or indicate a part removed for clarity.