Engineering Drawing k Is the language of engineers and technicians. The accuracy and neatness of engineering drawing depends on the quality of the instruments used. With good instruments, the drawing can be prepared easily, quickly and accurately. Therefore, the knowledge of different drawing instruments and materials, methods of using them and the preparatory works to be completed before commencing the drawing is very important. Else Of Engineering Instruments 1. Drawing Board . A drawing board with its working surface upward. Else as a base for drafting on paper .
Drawing Sheet – The drawing is frequently made in pencil on the drawing sheet. 3. Drawing Pencil – Neatness, quality and accuracy of the drawing greatly depends upon the type and conditions of the pencil used for drawing. 4. Drawing Clips Or Pins – Drawing clips or pins are used to fix the drawing sheet on the drawing board at the required place. Clips are used at all the four corners of the drawing board to clamp the paper _ Adhesive tapes are also used for fixing the drawing sheet. 5. Eraser – Eraser is used to remove the extra lines, lines,’marks drawn by stake and to clear soiled spots on the drawing. . Erasing Shield – It is a thin metal or plastic plate cut vita slots, circles and curves of different dimensions. It helps to erase unwanted pencil lines Without erasing the surrounding lines. 7. T- Square – It is composed Off long strip called blade, Which is screwed rigidly at right angle to a shorter piece called head or stock. T- Square is used for making horizontal, vertical, inclined or parallel lines on the drawing sheet. 8. Set-Squares . Set-squares are made of transparent plastic and are available n the shape of triangles, having a French curve or simply a gap cut in the body.
These are used for drawing short straight lines, measuring and drawing certain angles. 9. Large Size Compass – The compass is used for drawing circles and arcs, 10. Small Boob Compass – Small bow compass is conveniently used for drawing circles and arcs of small diameters. II, r-ranch Curves – French curves are used to draw irregular curved lines, which can not be drawn with a compass. 12. Large Size Divider – used to divide straight or curved lines into desired umber Of equal parts, set Off distances from the scale to the drawings & transfer measurements from one part of the drawing to another. 3. Small Bow Divider – The small bow divider is adjusted by a nut and is very convenient for marking minute divisions and large number Of short equal distances. Scales 14. Scales – is a tool for measuring distances and transferring measurements at a fixed ratio of length. 15. Protractors – used for drawing any desired angle. 16. Mini Drafter – It’s an instrument used to draw geometrical shapes and usuries With great precision, It does not require any other instrument like scale, set squares or compass. Proper care of Engineering Instruments 1.
Pencil a. Never sharpen the pencil over the drawing or close to any of your b. Always keep the lead sharp. Equipment. 2. T-square, triangles and Greene curves a. Do not use the T-square for any rough purposes. B. Never cut paper along its working edge, since the plastics can easily be damaged. Even light nick can ruin the T-square. 3. Ruler or scale a. Scales should not be pricked With needle points Of either the divider or mommas when measurements are taken. B. Do not use scale as a ruler. 4. Speedwell pens and lettering pens a.
After using, clean the speed bullpen by wiping-off or scraping the ink on it with clean cloth, which is a little wet or you may use blade for scrapping. B. Lettering pens, like technical pens, should be clean at once with clean water and soap. Wipe it off with clean cloth. S. Dividers and compasses a. Do not oil the joints of the legs of the dividers. B. Do not use the divider as substitute for thumbtacks in fastening the drawing paper on the drawing board or table top. . The needle points must be sharp and of equal length. . Drawing paper a. It should be stored in rolled for, b. It should not be crumpled or wet or kept in a moist or cold place. C. Oslo papers or bond papers must be kept in a large envelope. I, Masking tape or scotch tape, eraser and erasing shield a. Should be kept together with other supplies to avoid losing it. 8. Drawing board or drawing tape a. It should always be in good (drawing) working condition. B. It must always be clean on or before using. C. Do not leave any kind of marks on your board to retain its smoothness.
