INSTRUMENTS USED IN TECHNICAL DRAWING
The completion of a technical drawing requires calculation, measurement, well-planned lines, precision end, a number of conditions that necessitate the use of good tools, good materials, and added to this, theoretical knowledge into practice are united stand a cartoonist.
It is a drawing tool on down the paper for drawing. Usually constructed of wood or plastic smooth and flat, straight edges which enables movement of the rule T.
The size depends on the format being used. For the school format is sufficient in size from 40 inches tall and 60 centimeters wide.
In the workshops of technical drawing, instead of boards, built tables are used only for this activity, the size and inclination.
The rule T gets its name from its resemblance with the letter T. Has two perpendicular arms. The cross arm is shorter. They are made of wood or plastic.
It is used to draw horizontal parallel lines quickly and accurately. It also serves as a support to the squads and to align the format and proceed to fixing.
It is an instrument to measure and draw straight lines, its shape is rectangular, flat and has at its edges recordings decimeters, centimeters and millimeters.
They are usually of wood or plastic. Although clear plastic preferred to see the lines that are plotted.
Their lengths vary according to usage, ranging from 10 to 60 inches The most common are 30 centimeters.
The brackets are used to measure and draw horizontal, vertical, inclined, and combined with the rule T are drawn parallel, perpendicular and oblique. Graduates can take inches and millimeters.
The brackets that are used in technical drawing are two:
- The 45 degree which is shaped like an isosceles triangle with an angle of 90 ° and two of 45 º.
- The squad of 60 º bevel also called shaped like a scalene triangle, whose angles measure 90 º, 30 º and 60 º.
It is an instrument used for measuring angles or transport. They are made of plastic and are of two types: in a semicircle divided into 180 degrees in a circle and full 360 º.
The numbers are arranged in two graduation so they can be read from right to left and from left to right, depending on where is the opening angle.
It is a precision instrument that is used to draw arcs, circles and transportation measures.
It consists of two articulated arms at the top which houses a cylindrical piece which called mango drink and drive with the index finger and thumb.
One arm has an adjustable steel needle with a screw and a nut on a wheel. The other arm has a device that allows the placement of pencils or other accessories.
- Part Compass: Compass is normal that you can put accessories like pencil or pen.
-Compass dry ends: it has sharp points at both ends of steel and serves to take action or move.
- Compass mustache, is characterized by keeping fixed the radius of opening. The opening of this bar is graduating with a screw or threaded shaft. It is used to develop small-sized circles and circles of equal radius.
- Compass pump: used to draw arcs or circles very small. Arm consists of a vertical shaft that serves to turn the pencil around it.
The pencils are essential for writing and drawing. They consist of a graphite mine and a sheath of wood. They can be round or hexagonal cross section. To draw the hexagon are better because they facilitate the attachment between the fingers and prevent it from rolling to leave them on the drawing board.
Degrees of hardness of the mine.
The pencil leads has several degrees from the hardest to the softest. Over the last mine fine lines are drawn in gray and bold lines and softer black.
Are classified by letters and numbers. The H comes from the word meaning hard drive, the F stands firm and black B which means black.
The hardest are: 4H, 3H, 2H and H. Intermediates are: HB and F. The softer are: B, 2B, 3B and 4B.