A drafting machine is a very useful tool in technical drawing

Technical drawing

Technical drawing, also known as drafting or draughting, is the act and discipline of composing plans that visually communicate how something functions or has to be constructed.Drafting is the language of industry....

, consisting of a pair of scales mounted to form a right angle on an articulated protractor

Protractor

In geometry, a protractor is a circular or semicircular tool for measuring an angle or a circle. The units of measurement utilized are usually degrees.Some protractors are simple half-discs; these have existed since ancient times...

 head that allows an angular rotation

Rotation

A rotation is a circular movement of an object around a center of rotation. A three-dimensional object rotates always around an imaginary line called a rotation axis. If the axis is within the body, and passes through its center of mass the body is said to rotate upon itself, or spin. A rotation...

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The protractor head (two scales and protractor mechanism) is able to move freely across the surface of the drawing board

Drawing board

A drawing board is, in its antique form, 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 or other oversized document or for drafting precise technical illustrations...

, sliding on two guides directly or indirectly anchored to the drawing board. These guides, which act separately, ensure the movement of the set in the horizontal or vertical direction of the drawing board

Drawing board

A drawing board is, in its antique form, 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 or other oversized document or for drafting precise technical illustrations...

, and can be locked independently of each other.
Drafting machines were present in the design offices of European companies since the 1920s. It is curious to see how the Encyclopaedia Britannica explicitly specifies 1930 as the year this tool was introduced, but an advertisement of "Memorie di architettura pratica" from 1913 places it twenty years before this date — at least in Italy.

In the older design sets, the movement of the protractor head was assured by a parallelogram

Parallelogram

In Euclidean geometry, a parallelogram is a convex quadrilateral with two pairs of parallel sides. The opposite or facing sides of a parallelogram are of equal length and the opposite angles of a parallelogram are of equal measure...

 system that could keep the head in the same angular

Angle

In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.Angles are usually presumed to be in a Euclidean plane with the circle taken for standard with regard to direction. In fact, an angle is frequently viewed as a measure of an circular arc...

 position throughout its range of motion. The arms were balanced by a system of counterweights or springs

Spring (device)

A spring is an elastic object used to store mechanical energy. Springs are usually made out of spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication...

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Typically, the machine is mounted on a drawing board

Drawing board

A drawing board is, in its antique form, 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 or other oversized document or for drafting precise technical illustrations...

 with a hard and smooth surface, anchored to a base that allows its tilting

Tilting

Tilting may refer to:* Tilt , a cinematographic technique* Tilting train, a train with a mechanism enabling increased speed on regular railroad tracks* Tilting, Newfoundland and Labrador, a town on Fogo Island* Tilting, a type of jousting...

 and lifting

Lifting

Lifting may refer to:*Weightlifting*Shoplifting*Facelift*An undesirable type of movement in the sport of racewalking.*Taking an inference rule in propositional logic and adapting it for predicate logic*Lift *Lifting scheme...

. Thus, the realization of a drawing

Drawing

Drawing is a form of visual art that makes use of any number of drawing instruments to mark a two-dimensional medium. Common instruments include graphite pencils, pen and ink, inked brushes, wax color pencils, crayons, charcoal, chalk, pastels, markers, styluses, and various metals .An artist who...

 can be achieved in the most convenient way on a working surface that can be tilted at any angle from horizontal to vertical.

There are special versions for A0

ISO 216

ISO 216 specifies international standard paper sizes used in most countries in the world today. It defines the "A" and "B" series of paper sizes, including A4, the most commonly available size...

 double-sized boards, to make large drawings, or copying-boards with background illumination, which have all that is necessary to provide specific support.

With the drafting machine one can perform a series of drawing operations that otherwise could only be achieved with a much more complex use of the classic ruler

Ruler

A ruler, sometimes called a rule or line gauge, is an instrument used in geometry, technical drawing, printing and engineering/building to measure distances and/or to rule straight lines...

 square

Combination square

A combination square is a tool used for multiple purposes in woodworking, stonemasonry and metalworking. It is composed of a ruled blade and one or more interchangeable heads that may be affixed to it...

 and protractor

Protractor

In geometry, a protractor is a circular or semicircular tool for measuring an angle or a circle. The units of measurement utilized are usually degrees.Some protractors are simple half-discs; these have existed since ancient times...

, as, for example, drawing parallel

Parallel (geometry)

Parallelism is a term in geometry and in everyday life that refers to a property in Euclidean space of two or more lines or planes, or a combination of these. The assumed existence and properties of parallel lines are the basis of Euclid's parallel postulate. Two lines in a plane that do not...

 line

Line

- Science and technology :* Line , a circuit or loop.** A power line for electric power transmission** line power or lines power, domestic mains electricity.** telephone line** RF transmission line...

s, orthogonal lines, inclined lines according to a preset angle, measurement of angle

Angle

In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.Angles are usually presumed to be in a Euclidean plane with the circle taken for standard with regard to direction. In fact, an angle is frequently viewed as a measure of an circular arc...

s, etc.

With the development of computer-aided design

Computer-aided design

Computer-aided design , also known as computer-aided design and drafting , is the use of computer technology for the process of design and design-documentation. Computer Aided Drafting describes the process of drafting with a computer...

 (CAD), the use of drafting machines, especially in the professional sector, has been drastically reduced, and nowadays the role for achieving drawings on paper is relegated to the computer-driven plotter

Plotter

A plotter is a computer printing device for printing vector graphics. In the past, plotters were widely used in applications such as computer-aided design, though they have generally been replaced with wide-format conventional printers...

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