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Set square (IS:1361-1988): Transparent celluloid /Plastic setsquares are preferred and are commonly used rather ebonite ones. They are two in number, each having one corner with 90°. The setsquare with 60°-30° of 250 mm long and 45° of 200mm long is convenient for use. Setsquares sometimes loose their accuracy due to internal strains. So they should be tested periodically

Sometimes set squares have french curves. Set squares are used to draw all straight lines except horizontal lines. It is convenient to draw horizontal lines using Mini drafter.

Main Types of Engineering Drawing

Engineering drawing is used in all branches of engineering. However, based on major engineering fields, it can be classified into the following types:

1. Mechanical Engineering Drawings:

These drawings are related to machine parts and assemblies used in mechanical engineering.

These are made in many different shapes, normally come in sets of 6,12,16 etc. French curves are best suited to draw smooth curves/ arcs (which cannot be drawn by a compass) with ease. To draw a smooth curve using french curve first set it by trial against a part of the line to be drawn, then shift it to the next portions. Each new portion should fit atleast three points on the curve just drawn. It should be seen that the curve (radius) is increasing or decreasing smoothly and no corner should be formed on the curve

Purpose of studying engineering drawing:

• To develop the ability to produce simple engineering drawing and sketches based on current practice
• To develop the skills to read manufacturing and construction drawings used in industry.
• To develop a working knowledge of the layout of plant and equipment.
• To develop skills in abstracting information from calculation sheets and schematic diagrams to produce working drawings for manufacturers, installers and fabricators.

बड़ा डिवाइडर एक महत्वपूर्ण ड्रॉइंग उपकरण है जिसका उपयोग माप (dimensions) को स्थानांतरित (transfer) करने तथा रेखाओं को समान भागों में विभाजित करने के लिए किया जाता है।

Technical drawings allows efficient communication among engineers and can be kept as a record of the planning process. Since a picture is worth a thousand words, a technical drawing is a much more effective tool for engineers than a written plan.

It has a knee joint in one leg that permits the insertion of pen or pencil point or attaching lengthening bar with pen or pencil point attached to it. It is used for drawing large circles/arcs also for taking large measurements. The pin on the other leg can be swivelled to vertical position when drawing large circles, while drawing the circles of arcs it should be held in such a way that the needle point leg and pencil point leg should be bent so as to make perpendicular to the paper.

The economical success of any country is mainly depended on its industrial development. Due to the globalization any industry of our country expected to be of global market standard. Due to the above said reason our Indian product required to be of very high quality with respect to size of dimension, fit, tolerance and finish etc.

When, on a drawing, if a part of a line or some lines among many other lines need to be erased or modified, in normal way of erasing will damage the other nearby lines. In such a situation an erasing shield is effectively useful. It is a thin metallic sheet having small openings of different sizes and shapes. A suitable opening is aligned to the line to be erased and the line is removed by the eraser.

A drawing is a graphical representation of an object, or part of it, and is the result of creative thought by an engineer or technician. When one person sketches a rough map in giving direction to another, this is graphic communication. Graphic communication involves using visual materials to relate ideas. Drawings, photographs, slides, transparencies, and sketches are all forms of graphic communication. Any medium that uses a graphic image to aid in conveying a message, instructions, or an idea is involved in graphic communication.