Technical Drawing Instruments

The drawing board is a flat, smooth surface on which a piece of paper can be placed in order to facilitate drawing.

There are several models of drawing boards. They can be made of wood, glass, etc., and can be  portable or fixed. The following image shows a model of a portable drawing board made of plastic.

The T-square is an instrument consisting of a head and a blade, usually made of wood or steel. The T-square is used to draw horizontal lines.

The T-square is also used to draw vertical lines and draw oblique lines by pressing a set square against the blade of the T-square.

The white drawing sheet serves as the support on which the drawing is traced.

The sheet is usually taped to a drawing board.

The millimetric grid sheet, also known as graph paper or grid paper, is used to make several types of projections. Horizontal and vertical reference lines are spaced at |1\ \text{mm}.|

This type of grid sheet allows drawing lines of various dimensions without the need for a ruler. For example, to draw a straight line of |15\ \text{mm},| we count |15| small squares on the grid sheet.

The sheet is usually taped to a drawing board.

The isometric paper sheet allows isometric projections to be made, as it includes reference lines oriented at |120^\circ| to each other.

The sheet is usually taped to a drawing board.
 

The triangular ruler can be used to measure and trace straight lines of various lengths.

A triangular ruler includes up to six different scales. We choose the border of the ruler that features the desired scale.
For example, if we use the scale |1:20| on the ruler, this means that a measurement of |1\ \text{mm}| on the drawing corresponds to a measurement of |20\ \text{mm}| on the real object.

The |45^\circ| set square is used to draw oblique lines to |45^\circ| and vertical lines.

When using a set square, you usually rest it on the blade of the T-square and slide it to where you want to draw a line.

The |30^\circ| — |60^\circ| set square is used to draw oblique lines to |30^\circ| or |60^\circ| as well as perpendicular lines.

When using a set square, you usually rest it on the blade of the T-square and slide it to where you want to draw a line.

A protractor is used to measure angles as well as to draw oblique lines at various angles.

The compass is used to draw circles and arcs of circles of different radii.

One arm of the compass has a metal point called a dry point. The dry point has to be placed on the centre of the circle to be traced. The other limb has a pencil lead for tracing. Between the two branches, a worm and worm gear system adjusts the opening of the branches.

The compass can also be used to compare distances or report a measurement.

The circle template is used to draw circles of different diameters or arcs of circles.

For each circle on the template, there is the diameter measurement in millimetres |\text{(mm)}.| We need to choose the circle that corresponds to the one we want to trace.

Around the circles, there are symmetry lines. They must be aligned with the axis lines on the drawing.

The ellipse template is used to draw ellipses of various sizes.

Each ellipse on the template includes its measurements in millimetres |\text{(mm)}.| We need to choose the ellipse that corresponds to the one we want to draw.

Around the ellipses are the symmetry lines, which must be aligned with the axis lines on the drawing.
 

The French curve is a template used to draw curves. It has several sections with curves of different radii.

The drawing template hides part of the drawing so the desired strokes can be erased.

The 2H pencil is used to sketch a drawing thanks to its hard graphite lead that leaves a fine pale line.

The HB pencil darkens the lines of the final drawing thanks to its oilier graphite lead that leaves a thick dark line.

The eraser is used to make corrections to a drawing.

Adhesive tape is used, among other things, to tape a sheet of paper to a drawing board.

Generally, we choose a tape that doesn't damage the drawing sheet, such as painter's tape or masking tape.
 

The calculator is used to make calculations when necessary.