Mechanical Fasteners and Dimensioning Standards
Dimensioning Standards
Dimensions should be placed in the most descriptive view of the feature being dimensioned. A feature should be dimensioned only once. Each feature should be dimensioned or identified with a note. Dimension features or surfaces should be done to a logical reference point. Center lines or center marks should be used on all circles, holes, and slots. Arrowheads are used to terminate dimension lines. The point of the arrowheads on the leader line must make contact with the feature
Read MoreEngineering Drawing: Essential Concepts and Techniques
Unit 6: Development of Surfaces
1. What is the Significance of Development?
Development is a graphical method of obtaining the area of the surfaces of a solid. In engineering, many objects cannot be manufactured by conventional manufacturing processes because of their size and shape. Thus, they are fabricated using the development phenomenon from metal sheets. Some examples include boiler shells and chimneys, pressure vessels, shovels, trays, boxes and cartons, feeding hoppers, large pipe sections,
Read MoreEngineering Drawings and Design Development
Drawing Types and Scales
In engineering, most design information is shown on drawings. Today, drawings are generally not drawn by hand. They are produced on a computer, using CAD (Computer-Aided Design) systems.
A key factor on a drawing is the scale – that is, the size of items on the drawing in relation to their real size. When all the items on a drawing are shown relative to their real size, the drawing is drawn to scale and can be called a scale drawing. An example of a scale is 1:10 (one to ten)
Read MoreRefrigeration, Computers, Friction, Sustainability, and Piper Alpha
Refrigeration and Air Conditioning History
Before engineers learned how to cool air, life was very different. Food had to be bought the same day it was used. Most foodstuffs couldn’t be transported long distances, so people had to live close to the source of food. The inventor of refrigeration was Jacob Perkins. He was American, but he lived most of his life in Britain. He invented a machine for cutting and heading nails, and he was the first person to use steel to make plates for engraving banknotes.
Read MoreTechnical Drawing Standards
Norms for Graphic Representation
A technical drawing is the graphic representation, clear, correct, and precise, of a piece on paper. It should be sufficient to fully define clear forms, not collecting unnecessary data.
Drawing Classes
- Design conception: Sketch or schema drawing.
- Definition drawing: Design and manufacturing.
Line Types
Drawings use shapes and lines of varying thickness, as applicable:
- Full line
- Dashed line
- Dash-dotted line
- Freehand line
Drawing Elements in Industry
Its purpose is to inform
Read MoreTechnical Drawing: Types, Importance, Lines, Format, and Scales
Concept of Drawing
Drawing is the art of representing natural and artificial forms, as well as forms designed by the human mind, on a surface.
- Artistic Drawing: Executed freely and with aesthetic purposes.
- Technical Drawing: Performed with various aids, according to conventional standards for practical purposes. Precision instruments are used.
Types of Technical Drawing
- Architectural Drawing: Includes all graphic representations through which the construction of buildings, houses, villas, churches, etc.