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Drafting tools may be used for measurement and layout of drawings, or to improve the consistency and speed of creation of standard drawing elements. Tools such as pens and pencils mark the drawing medium. Other tools such as straight edges, assist the operator in drawing straight lines, or assist the operator in drawing complicated shapes repeatedly. Various scales and the protractor are used to measure the lengths of lines and angles, allowing accurate scale drawing to be carried out. The compass is used to draw arcs and circles. A drawing board was used to hold the drawing media in place; later boards included drafting machines that sped the layout of straight lines and angles. Tools such as templates and lettering guides assisted in the drawing of repetitive elements such as circles, ellipses, schematic symbols and text. Other auxiliary tools were used for special drawing purposes or for functions related to the preparation and revision of drawings. The tools used for manual
technical drawing Technical drawing, drafting or drawing, is the act and discipline of composing drawings that visually communicate how something functions or is constructed. Technical drawing is essential for communicating ideas in industry and engineering ...
have been displaced by the advent of computer-aided drawing, drafting and design ( CADD).


History

The ancient Egyptians are known to have used wooden corner rulers. Ancient Nuragic people in
Sardinia Sardinia ( ; it, Sardegna, label=Italian, Corsican and Tabarchino ; sc, Sardigna , sdc, Sardhigna; french: Sardaigne; sdn, Saldigna; ca, Sardenya, label= Algherese and Catalan) is the second-largest island in the Mediterranean Sea, aft ...
used compasses made of bronze, like the one displayed in showcase 25 in the Nuragic department of the National Archeological Museum G. A. Sanna in
Sassari Sassari (, ; sdc, Sàssari ; sc, Tàtari, ) is an Italian city and the second-largest of Sardinia in terms of population with 127,525 inhabitants, and a Functional Urban Area of about 260,000 inhabitants. One of the oldest cities on the island ...
. In ancient Greece, evidence has been found of the use of styli and metal chisels, scale rulers and triangle rulers. Excavations in Pompeii have found a bronze tool kit used by the Romans, which contained triangle rulers, compasses and a ruler to use with a pen. Although a variety of styli were developed in ancient times and were still being used in the 18th century,
quill A quill is a writing tool made from a moulted flight feather (preferably a primary wing-feather) of a large bird. Quills were used for writing with ink before the invention of the dip pen, the metal- nibbed pen, the fountain pen, and, eve ...
s were generally used as the main drawing tool. Styli were also used in the form of
ivory Ivory is a hard, white material from the tusks (traditionally from elephants) and teeth of animals, that consists mainly of dentine, one of the physical structures of teeth and tusks. The chemical structure of the teeth and tusks of mammals i ...
or
ebony Ebony is a dense black/brown hardwood, coming from several species in the genus '' Diospyros'', which also contains the persimmons. Unlike most woods, ebony is dense enough to sink in water. It is finely textured and has a mirror finish when ...
pencils.
Protractor A protractor is a measuring instrument, typically made of transparent plastic or glass, for measuring angles. Some protractors are simple half-discs or full circles. More advanced protractors, such as the bevel protractor, have one or two sw ...
s have been used to measure and draw angles and arcs of a circle accurately since about the 13th century, although mathematics and science demanded more detailed drawing instruments. The adjustable corner ruler was developed in the 17th century, but a feasible screw-tightened version not until the 1920s. In the 17th century, a stylus that could draw a line with a specific width called a
ruling pen A ruling pen is a drawing instrument for drawing with ink or with other drawing fluids. Originally used for technical drawings in engineering and cartography together with straight rulers and French curves, it is today used for specific uses, suc ...
was developed. The stylus had two curved metal pieces which were joined by a screw. Ink was trickled between the blades, from which it flowed evenly across the paper. The basic model was maintained for a long time, with minor modifications, until the 1930s when the German technical drawing pens came to the market. Artists (including
Leonardo da Vinci Leonardo di ser Piero da Vinci (15 April 14522 May 1519) was an Italian polymath of the High Renaissance who was active as a painter, draughtsman, engineer, scientist, theorist, sculptor, and architect. While his fame initially rested on ...
and
Albrecht Dürer Albrecht Dürer (; ; hu, Ajtósi Adalbert; 21 May 1471 – 6 April 1528),Müller, Peter O. (1993) ''Substantiv-Derivation in Den Schriften Albrecht Dürers'', Walter de Gruyter. . sometimes spelled in English as Durer (without an umlaut) or Due ...
, Nicholas Bion and George Adams) generally made drawing tools for themselves. Industrial production of technical drawing instruments started in 1853, when Englishman William Stanley (1829–1909) founded a technical manufacturing company in London. Even then, however, most tools were still made by hand. In the 1930s the equipment available expanded: drawing apparatus and Rapidograph-drawing pens appeared, improving the line quality and, especially, producing consistent line width. In addition to the Rapidograph stylus, a more traditional Grafos-type stylus was used for a long time, where different line widths were achieved by changing the pen nib. For instance in Finland Grafos was commonly used as a primary drawing tool still in the early 1970s. Equipment changed radically during the 1990s, when
computer-aided design Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve co ...
almost completely ousted drawing by hand. Technical design has changed from drawing by hand to producing computer-aided design drawings, where drawings are no longer "drawn", but are built from a virtually-produced model. Drawings are not necessarily produced in hard copy at all, and if they are needed they are printed automatically by a computer program. Hand-drawn designs however are still widely used in the draft design stage.


Drawing tools


Pencil

Traditional and typical styli used for technical drawing are
pencil A pencil () is a writing or drawing implement with a solid pigment core in a protective casing that reduces the risk of core breakage, and keeps it from marking the user's hand. Pencils create marks by physical abrasion, leaving a tra ...
s and
technical pen A technical pen is a specialized instrument used by an engineer, architect, or drafter to make lines of constant width for architectural, engineering, or technical drawings. " Rapidograph" is a trademarked name for one type of technical pen. T ...
s. Pencils in use are usually
mechanical pencil A mechanical pencil, also clutch pencil, is a pencil with a replaceable and mechanically extendable solid pigment core called a "lead" . The lead, often made of graphite, is not bonded to the outer casing, and can be mechanically extended as its ...
s with a standard lead thickness. The usual line widths are 0.35 mm, 0.5 mm, 0.7 mm and 1.0 mm. Hardness varies usually from HB to 2H. Softer lead gives a better contrast, but harder lead gives a more accurate line. Bad contrast of the lead line in general is problematic when photocopying, but new scanning copy techniques have improved the final result. Paper or plastic surfaces require their own lead types. In most cases, the final drawings are drawn with ink, on either plastic or
tracing paper Tracing paper is paper made to have low opacity, allowing light to pass through. It was originally developed for architects and design engineers to create drawings that could be copied precisely using the diazo copy process; it then found ma ...
. The pen is generally a Rapidograph-type technical pen, a marker pen that draws lines of consistent width (so-called steel marker pen). The pen has an ink container which contains a metal tube, inside which is a thin metal needle or wire, the soul. Ink is absorbed between the needle and the tube wall, preventing an excessive amount of ink from being released. The needle has a weight and by waving the pen back and forth the needle is released and the ink can run. Originally, the tank was filled from an ink bottle; newer pens use ink cartridges. Each line width has its own stylus. The line width is
standardized Standardization or standardisation is the process of implementing and developing technical standards based on the consensus of different parties that include firms, users, interest groups, standards organizations and governments. Standardization ...
: In Finland, the most commonly used set is , , , , and . Separate styli are used for tracing paper and plastic, because plastic requires a harder pen tip. To function well they require regular maintenance, the finest marker pens in particular.


Drafting board

The
drawing board A drawing board (also drawing table, drafting table or architect's table) 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 l ...
is an essential tool. Paper will be attached and kept straight and still, so that the drawing can be done with accuracy. Generally, different kind of assistance rulers are used in drawing. The drawing board is usually mounted to a floor pedestal in which the board turns to a different position, and also its height can be adjustable. Smaller drawing boards are produced for table-top use. In the 18th and 19th centuries, drawing paper was dampened and then its edges glued to the drawing board. After drying the paper would be flat and smooth. The completed drawing was then cut free. Paper could also be secured to the drawing board with drawing pins or even C-clamps. More recent practice is to use self-adhesive
drafting tape Drafting Tape, also known as artist's tape, is similar to masking tape in that it has a wide variety of uses, but differs in several key areas. # Drafting tape should not leave a sticky residue behind #Drafting tape is easily removable, even from d ...
to secure paper to the board, including the sophisticated use of individualized adhesive dots from a dispensing roll. Some drawing boards are magnetized, allowing paper to be held down by long steel strips. Boards used for overlay drafting or
animation Animation is a method by which still figures are manipulated to appear as moving images. In traditional animation, images are drawn or painted by hand on transparent celluloid sheets to be photographed and exhibited on film. Today, most ani ...
may include registration pins or peg bars to ensure alignment of multiple layers of drawing media.


T-square

A
T-square A T-square is a technical drawing instrument used by draftsmen primarily as a guide for drawing horizontal lines on a drafting table. The instrument is named after its resemblance to the letter T, with a long shaft called the "blade" and a sh ...
is a
straightedge A straightedge or straight edge is a tool used for drawing straight lines, or checking their straightness. If it has equally spaced markings along its length, it is usually called a ruler. Straightedges are used in the automotive service and m ...
which uses the edge of the drawing board as a support. It is used with the drafting board to draw horizontal lines and to align other drawing instruments. Wooden, metal, or plastic triangles with 30° and 60° angles or with two 45° angles are used to speed drawing of lines at these commonly used angles. A continuously adjustable 0–90°
protractor A protractor is a measuring instrument, typically made of transparent plastic or glass, for measuring angles. Some protractors are simple half-discs or full circles. More advanced protractors, such as the bevel protractor, have one or two sw ...
is also in use. An alternative to the T-square is the parallel bar which is permanently attached to the drawing board. It has a set of cables and pulleys to allow it to be positioned anywhere on the drawing surface while still remaining parallel to the bottom of the board. The drafting machine replaces the T-square and triangles.


Drafting machine

A
drafting machine A drafting machine is a tool used in technical drawing, consisting of a pair of scales mounted to form a right angle on an articulated protractor head that allows an angular rotation. The protractor head (two scales and protractor mechanism) is ...
is a device which is mounted to the drawing board. It has rulers whose angles can be precisely adjusted with a controlling mechanism. There are two main types of apparatus: an arm-type parallelogram apparatus based on a hinged arm; and a track-type apparatus which moves on a rail mounted to the top of the drawing board. The accuracy of the arm type apparatus is better in the middle of the board, decreasing towards the edges, whereas a track machine has a constant accuracy over the whole board. The drawing head of a track-type drafting machine slides on bearings in a vertical rail, which in turn is moved along a horizontal, top-mounted rail. Both apparatus types have an adjustable drawing-head with rules attached to a protractor scale so that the angle of the rules may be adjusted. A drafting machine allows easy drawing of parallel lines over the paper. The adjustable angle between the rulers allows the lines to be drawn in varying accurate angles. Rulers may also be used as a support for separate special rulers and letter templates. The rules are replaceable and they can be for example scale-rules. Drawing apparatus has evolved from a drawing board mounted parallel ruler and a
pantograph A pantograph (, from their original use for copying writing) is a mechanical linkage connected in a manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical movements in a second pen. If a line dr ...
, which is a device used for copying objects in an adjustable ratio of sizes.


French curves

French curve A French curve is a template usually made from metal, wood or plastic composed of many different segments of the Euler spiral (aka the clothoid curve). It is used in manual drafting and in fashion design to draw smooth curves of varying radii. ...
s are made of wood, plastic or celluloid. Some set squares also have these curves cut in the middle. French curves are used for drawing curves which cannot be drawn with compasses. A faint freehand curve is first drawn through the known points; the longest possible curve that coincides exactly with the freehand curve is then found out from the French curves. Finally, a neat continuous curve is drawn with the aid of the French curves.


Rulers

Ruler A ruler, sometimes called a rule, line gauge, or scale, is a device used in geometry and technical drawing, as well as the engineering and construction industries, to measure distances or draw straight lines. Variants Rulers have long ...
s used in technical drawing are usually made of
polystyrene Polystyrene (PS) is a synthetic polymer made from monomers of the Aromatic hydrocarbon, aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin pe ...
. It is used for drawing lines and connecting points. Rulers come in two types according to the design of their edge. A ruler with a straight edge can be used with lead pencils and felt pens, whereas when a
technical pen A technical pen is a specialized instrument used by an engineer, architect, or drafter to make lines of constant width for architectural, engineering, or technical drawings. " Rapidograph" is a trademarked name for one type of technical pen. T ...
is used the edge must be grooved to prevent the spread of the ink. A scale ruler is a scaled, three-edged ruler which has six different scales marked to its sides. A typical combination for building details is 1:20, 1:50, 1:100, 1:25, 1:75 and 1:125. There are separate rulers for zoning work as well as for inch units. Today scale rulers are made of plastic, formerly they were made of
hardwood Hardwood is wood from dicot trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood (which comes from ...
. A pocket-sized version is also available, with scales printed on flexible plastic strips.


Compass

Compasses are used for drawing circles or arc segments of circles. One form has two straight legs joined by a hinge; one leg has a sharp pivot point and the other has a holder for a
technical pen A technical pen is a specialized instrument used by an engineer, architect, or drafter to make lines of constant width for architectural, engineering, or technical drawings. " Rapidograph" is a trademarked name for one type of technical pen. T ...
or pencil. Another form, the
beam compass A beam compass is a compass with a beam and sliding sockets or cursors for drawing and dividing circles larger than those made by a regular pair of compasses. The instrument can be as a whole, or made on the spot with individual sockets (called ...
, has the pivot point and pen holder joined by a trammel bar, useful when drawing very large radius arcs. Often a circle template is used instead of a compass when predefined circle sizes are required.


Templates

Templates contain pre-dimensioned holes in the right scale to accurately draw a symbol or sign. Letter templates are used for drawing text, including digits and letter characters. Diagrams are usually of a standard letter shape and size to conform to standards of encodings (e.g. DIN or ANSI). For example, in Finland the series used is 1.8 mm, 2.5 mm, 3.5 mm, 5.0 mm and 7.0 mm. Except for the very biggest ones, the templates are only suitable for technical pen drawing. For drawing circles and circle-arcs, circle templates which contain a set of suitably-sized holes are used. Templates are also available for other geometric shapes such as squares and for drawing ellipses, as well as many specialized varieties for other purposes. There are also specific templates to provide user with the most common symbols in use in different branches of designing. For example, the architect templates can be used to draw different sized doors with their "opening arcs", building and equipment symbols and furniture. The templates also provide the symbols for thermal insulation. Two methods of drawing smooth curves in manual drafting are the use of
French curve A French curve is a template usually made from metal, wood or plastic composed of many different segments of the Euler spiral (aka the clothoid curve). It is used in manual drafting and in fashion design to draw smooth curves of varying radii. ...
s and flat splines (flexible curves). A French curve is a drawing aid with many different smoothly-varying radiused curves on it; the manual drafter can fit the French curve to some known reference points and draw a smooth curved line between them. A spline is a flexible ruler, usually rubber or plastic coated with a metal "backbone", which can be smoothly shaped to follow a desired curve and allows drawing a smooth line between initial reference points. Sometimes a spline is temporarily held in position with small weights.


Perspective machines

A perspective machine is an instrument designed to create perspective drawings."Perspective Machine", ''The New and Complete American Encyclopedia'', John Low, 1810, p. 441


Drawing materials


Drafting paper

Silk-paper-like translucent drafting paper that wrinkles when wetted. It is primarily suitable for pencils and felt tip pens. Pencil marks can be corrected to some extent with an eraser.


Thick draft paper

Sandwich-paper-like, thin translucent sheet of paper. Manufactured in different strengths, the surface may be slightly polished. This paper also wrinkles upon wetting. Suitable for pencil and felt tipped pens, and with limitations for technical pens. An eraser can be used for pencil lines. Ink is difficult to erase without damage.


Cloth

Drafting linen was formerly used for technical drawings. It was durable and held up to handling, but it was difficult to use in modern
whiteprint Whiteprint describes a document reproduction produced by using the diazo chemical process. It is also known as the blue-line process since the result is blue lines on a white background. It is a contact printing process which accurately reproduc ...
s for reproduction, and shrinking was a concern.


Tracing paper

Polished sandwich paper-like, translucent thick paper, which comes in different strengths. Wrinkles upon wetting. Suitable for both graphite pencils and technical pens. An eraser or sharp scraper tool is used for corrections.


Tracing tube

Translucent plastic film, which is usually of gray or a light khaki shade. Common types are 0.05, 0.07 and 0.10 mm thick. These films are also used in
photocopying A photocopier (also called copier or copy machine, and formerly Xerox machine, the generic trademark) is a machine that makes copies of documents and other visual images onto paper or plastic film quickly and cheaply. Most modern photocopier ...
. The most commonly used materials are
polyester Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include natura ...
s, and sometimes also PVC or
polycarbonate Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily work ...
; arguably, a proprietary eponym or genericized trademark for this is called
Mylar BoPET (biaxially-oriented polyethylene terephthalate) is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical and dimensional stability, transparency, reflectivity, gas and a ...
.


Inks

Drawing inks can be divided into two groups: India ink and polymer inks. India ink is used on paper and drafting film plastics. The most commonly used India ink is a colloidal mixture of water and
carbon black Carbon black (subtypes are acetylene black, channel black, furnace black, lamp black and thermal black) is a material produced by the incomplete combustion of coal and coal tar, vegetable matter, or petroleum products, including fuel oil, fluid ...
.


Dry transfer

Dry transfer decals can speed the production of repetitive drawing elements such as borders, title blocks, line types, shading, and symbols. They were frequently used in the production of schematic drawings, maps, and
printed circuit board A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich str ...
artwork, for example. Dry transfer lettering such as
Letraset Letraset was a company known mainly for manufacturing sheets of typefaces and other artwork elements using the dry transfer method. Letraset has been acquired by the Colart group and become part of its subsidiary Winsor & Newton. Corporate his ...
was used especially in lettering larger size document annotations, or when consistency of lettering was especially required.


Reproduction

Many copies of technical drawings may be required in the construction of a project. Reproductions must be accurate as to size and shape, but for many purposes need not be permanent. The
blueprint A blueprint is a reproduction of a technical drawing or engineering drawing using a contact print process on light-sensitive sheets. Introduced by Sir John Herschel in 1842, the process allowed rapid and accurate production of an unlimited number ...
process was first used for mechanical reproduction of drawings. Drawing offices may use
diazo The diazo group is an organic moiety consisting of two linked nitrogen atoms ( azo) at the terminal position. Overall charge neutral organic compounds containing the diazo group bound to a carbon atom are called diazo compounds or diazoalkanes ...
or
whiteprint Whiteprint describes a document reproduction produced by using the diazo chemical process. It is also known as the blue-line process since the result is blue lines on a white background. It is a contact printing process which accurately reproduc ...
processes. Where the volume of drawings reproduced justifies the cost of the machine, a large format photocopier using
xerography Xerography is a dry photocopying technique. Originally called electrophotography, it was renamed xerography—from the roots el, ξηρός, label=none ''xeros'', meaning "dry" and -γραφία ''-graphia'', meaning "writing"—to emphasiz ...
can reproduce drawings at lower cost than re-plotting them.


See also

* * * * * *


References


Further reading

* * * Pere, Aimo (in Finnish) ''Koneenpiirustus 1 & 2'' (''Machine Drawing 1 & 2'') Kirpe, 2004.


External links

* * {{DEFAULTSORT:Technical Drawing Tools Technical drawing Hand tools