The quality of the engineering drawing depends on the quality of the drawing instruments used. In order to create a clear and meaningful drawing, a good quality of the drawing instruments must be used. For a better drawing ,it is always recommended to use the drawing instruments with greater precision.
The instruments and other drawing tools used in the engineering drawing is given below.
- Drawing board
- Mini drafter
- Instrument box
- Set Square
- protractor
- set of scales
- French curves
- drawing sheets
- pencils
- templates.
Drawing Board
The drawing boards are generally made of softwood of about 25 mm thickness. This drawing board is used to Mount the mini drafter and the drawing sheet. The size of the board depends on the size of the drawing sheet required.
Large size drawing boards are used in the industrial area whereas small size drawing boards are used in schools and colleges.
Mini Drafter
A Mini Drafter is an instrument that can be used for several functions in the drawing. The Mini Drafter consists of two scales marked on it. It combines the function of a square, scale and protractor. The main function of the mini drafter is to draw the
- horizontal lines,
- vertical lines,
- inclined lines,
- parallel lines and
- perpendicular lines. It is also used for measuring the lines and angles in a drawing.
Mini Drafter is a useful tool for Civil and Mechanical engineering students. This told helps them to build and create a precise and a meaningful drawing.
Instrument box
The instrument box consists of the following
- compass,
- divider,
- inking pens
- Compass is a technical drawing tool which is used to draw circles.
- Whereas divider is a drawing instrument used for measuring and transferring the distances between two points. It consists of two straight legs which are adjustable and are hinged together with their ends Sharpened.
Scales:
The scales are made up of wood steel or plastic. Scales are used to measure or draw a line with specified measurements.
French Curves:
French curves are drawing templates made of plastic or wooden and are available in different shapes. The main purpose of the french curve is to draw smooth curve through the set of points.
Templates
The templates are plastic material used to draw small circle, squares, triangle and other shapes and symbols. Some alphabets and numbers can also be named using these templates.
Pencils:
Pencil is the key tool in engineering drawing. The softness or hardness of the pencil is indicated by 3H,2H H,HB.2B.3B, etc. The grade HB denotes medium hardness of lead used for general purpose. The hardness increases as the value of of the numeral before the letter H increases. The lead becomes softer as the value of the numeral before B increases.
The selection of the grid depends on the quality of the line used in the engineering drawing. pencil with softer grade are used for sketching purposes.
1hp grade is recommended for lettering and dimensioning
Soft grade (HB) for border lines, lettering and free sketching.
Medium grade(H) for visible outlines, visible edges and boundary lines.
Hard grade (2H) for construction lines, dimension lines, leader lines, extension lines, Centre lines, hatching lines and hidden lines.
Eraser
An eraser is used to to erase the the error or mistake in engineering drawing. A good quality of the eraser must be used in order to prevent mark or dust in the drawing sheet.
Set Square
A set square is a triangular plastic element for providing a straight edge at right angle or any other planar angle to a baseline.
Modern setsquares have protractor or any other curvy shapes marked on it.
Protractor
A protractor is a semicircle shaped drawing instrument with angles marked on its curved edge.The main purpose of the protractor is to measure angles in a drawing.
Also Read:
What is engineering drawing?