Technical Drawing Instruments Essay Example For Students

Technical Drawing Instruments Essay One of the shorter edges of the rectangular board is provided with perfectly straight bony edge which is used as working edge on which the T-square is moved while making Drawings. It is a kind of multipurpose desk, which can be used for any kind of drawing, writing or impromptu sketching on a large sheet of paper or for reading a large format book. Set square: A thin flat piece of plastic, metal, etc. , in the shape of a right-angled triangle, used in technical drawing, Set squares are generally made from Plastic or celluloid material. They are triangular in shape with one corner, a right angle triangle. We will write a custom essay on Technical Drawing Instruments specifically for you for only $16.38 $13.9/page Order now A pair of set squares (300-60) and 450(450) set square are generally provided with Protractor) facilitate marking of angles. T-square: A T-shaped ruler used in mechanical drawing, consisting Of a short crosspiece, which slides along the edge of the drawing board, and a long horizontal piece: used for drawing horizontal lines and to support set squares when drawing vertical and inclined lines Pencils: Pencils are rated on a scale of numbers and letters that describes the hardness of the graphite, Both hard and soft pencils have their uses in drawings, H Pencils:- H is the letter assigned to the hard graphite. A hard pencil produces a fine, light line. The hard pencils erase easily as long as you press lightly. If you press hard enough to indent the paper, youll never get rid of your line. B Pencils: A 8 indicates the softer pencils, again with the higher number being the softer graphite. A soft pencil will give a darker line. Youll want to be careful with these for two reasons: they can be difficult to erase completely, and if you press too hard your shadows can become reflective and metallic. Other Pencils: An 88 pencil, the standard pencil available almost anywhere, falls right in the middle. B B Hardest Medium Softest B=Blend Compass: H=Hardness Compass is used for drawing circles and arcs of circles. The compass has two legs hinged at one end. One of the legs has a pointed needle fitted at the lower end where as the other end has provision for inserting pencil lead. Circles up to mm diameters are drawn by keeping the legs of compass straight. For drawing circles more than 150 mm radiu s, a lengthening bar is used Eraser: An object, such as a piece of rubber or felt, used for erasing something written, typed, etc. A pencil eraser. Protractor: An instrument for measuring or drawing angles on paper, usually a flat noncircular transparent plastic sheet graduated in degrees. Protractors are used to mark or measure angles between O and 180. They are semicircular in shape (of diameter mm) and are made of Plastic or celluloid which has more life. Protractors With circular shape capable Of marking and measuring C to 3600 are also available in the market. Ruler: A pocket-sized measuring stick, the 6 inch tool used for the working in precision manufacturing. While a ruler may be used as a straight edge, a straight edge lacks the common markings necessary for measuring. Rulers and straight edges re usually made from strips of wood, plastic, or metal. Mechanical Pen: A propelling pencil or a pen pencil, with replaceable and mechanically extendable solid pigment core called lead. Scales. Any scale is called an engineers scale and is a tool for measuring distances and transferring measurements at a fixed ratio of length, It is commonly made of plastic or aluminum and is just over 12 inches (305 mm) long, leaving the ends unmarked so that the first and last measuring ticks do not Vera off. It is used in making engineering drawings, commonly called blueprints.