Compass That Draws Circles in Perspective
A beam compass and a regular compass
A compass with an extension accessory for larger circles
A bow compass capable of drawing the smallest possible circles
A compass, more accurately known as a pair of compasses, is a technical drawing musical instrument that tin be used for inscribing circles or arcs. As dividers, information technology can also be used every bit a tool to step out distances, in detail, on maps. Compasses can be used for mathematics, drafting, navigation and other purposes.
Prior to computerization, compasses and other tools for manual drafting were ofttimes packaged as a gear up[1] with interchangeable parts. Past the mid-twentieth century, circle templates supplemented the employ of compasses.[ commendation needed ] Today those facilities are more often provided past computer-aided blueprint programs, so the concrete tools serve mainly a didactic purpose in teaching geometry, technical drawing, etc.
Structure and parts [edit]
Compasses are usually made of metal or plastic, and consist of 2 "legs" connected by a swivel which can be adapted to permit changing of the radius of the circle drawn. Typically one leg has a spike at its stop for anchoring, and the other leg holds a drawing tool, such every bit a pencil, a short length of just pencil pb or sometimes a pen.
Handle [edit]
The handle, a pocket-sized knurled rod to a higher place the swivel, is usually about half an inch long. Users can grip information technology between their pointer finger and thumb.
Legs [edit]
There are ii types of leg in a pair of compasses: the straight or the steady leg and the adjustable 1. Each has a separate purpose; the steady leg serves as the basis or support for the needle indicate, while the adjustable leg can exist contradistinct in order to draw dissimilar sizes of circles.
Hinge [edit]
The screw through the hinge holds the two legs in position. The hinge can be adjusted, depending on desired stiffness; the tighter the hinge-spiral, the more accurate the compass's operation. The better quality compass, made of plated metal, is able to be finely adjusted via a small, serrated wheel usually fix between the legs (see the "using a compass" animation shown above) and it has a (dangerously powerful) bound encompassing the hinge. This sort of compass is often known as a "pair of Spring-Bow Compasses".
Needle point [edit]
The needle betoken is located on the steady leg, and serves every bit the center point of the circle that is near to be drawn.
Pencil lead [edit]
The pencil pb draws the circle on a particular paper or material. Alternatively, an ink nib or attachment with a technical pen may be used. The better quality compass, made of metal, has its slice of pencil atomic number 82 specially sharpened to a "chisel edge" shape, rather than to a point.
Adjusting nut [edit]
This holds the pencil pb or pen in identify.
Uses [edit]
Circles can exist fabricated by pushing 1 leg of the compasses into the newspaper with the spike, putting the pencil on the paper, and moving the pencil around while keeping the legs at the same angle. Some people who find this action difficult often concord the compasses still and move the paper round instead. The radius of the intended circle tin can be changed past adjusting the initial angle between the two legs.
Distances can exist measured on a map using compasses with two spikes, besides called a dividing compass (or merely "dividers"). The swivel is set in such a way that the distance betwixt the spikes on the map represents a sure distance in reality, and past measuring how many times the compasses fit betwixt two points on the map the distance between those points tin be calculated.
Compasses and straightedge [edit]
Compasses-and-straightedge constructions are used to illustrate principles of plane geometry. Although a real pair of compasses is used to draft visible illustrations, the platonic compass used in proofs is an abstract creator of perfect circles. The most rigorous definition of this abstruse tool is the "collapsing compass"; having drawn a circle from a given point with a given radius, information technology disappears; it cannot simply be moved to another signal and used to draw another circumvolve of equal radius (unlike a real pair of compasses). Euclid showed in his second proposition (Book I of the Elements) that such a collapsing compass could be used to transfer a distance, proving that a collapsing compass could practise anything a real compass tin do.
Variants [edit]
A beam compass is an instrument, with a wooden or brass axle and sliding sockets, cursors or trammels, for drawing and dividing circles larger than those made by a regular pair of compasses.[2]
Scribe-compasses [iii] is an instrument used by carpenters and other tradesmen. Some compasses can be used to describe circles, bifurcate angles and, in this case, to trace a line. Information technology is the compass in the most uncomplicated class. Both branches are crimped metal. One co-operative has a pencil sleeve while the other branch is crimped with a fine signal protruding from the end. A fly nut on the hinge serves two purposes: starting time it tightens the pencil and secondly information technology locks in the desired distance when the wing nut is turned clockwise.
Loose leg wing dividers [4] are made of all forged steel. The pencil holder, thumb screws, brass pivot and branches are all well congenital. They are used for scribing circles and stepping off repetitive measurements[5] with some accuracy.
A proportional compass, also known as a military compass or sector, was an instrument used for calculation from the stop of the sixteenth century until the nineteenth century. It consists of ii rulers of equal length joined by a hinge. Different types of scales are inscribed on the rulers that let for mathematical calculation.
A reduction compass is used to reduce or enlarge patterns while conserving angles.
As a symbol [edit]
A computer drawn compass, used to symbolize precise designing of applications.
A pair of compasses is often used as a symbol of precision and discernment. As such it finds a place in logos and symbols such as the Freemasons' Square and Compasses and in various computer icons. English poet John Donne used the compass as a conceit in "A Valediction: Forbidding Mourning" (1611).
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Compass for tracing a line.
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Apartment branch, pivot wing nut, pencil sleeve branch of the scribe-compass.
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vi inch (fifteen cm) dividers made from forged steel.
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One type of sector.
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The compass is a Masonic symbol that appears on jewellery such as this pendant.
See also [edit]
- Dividers
- Circumvolve
- Geometrography
- Masonic Square and Compasses
- Technical drawing tools
References [edit]
- ^ a electric current vendor's product
- ^
This commodity incorporates text from a publication now in the public domain:Chambers, Ephraim, ed. (1728). "Beam-Compasses". Cyclopædia, or an Universal Dictionary of Arts and Sciences (1st ed.). James and John Knapton, et al. - ^ Fine Woodworking, Build a Fireplace Mantel, Mario Rodriquez, pgs. 73, 75, The Taunton Press, No. 184, June 2006
- ^ The Carpenter'due south Manifesto, Jeffrey Ehrlich & Marc Mannheimer, Holt, Rhinehart & Winston, pg. 64, 1977
- ^ Fine Woodworking, Laying out dovetails, Chris Gochnour, pg. 31, The Taunton Press, No. 190, April 2007
External links [edit]
- Axle or trammel compass (variant class)
phillipsnestandmand.blogspot.com
Source: https://en.wikipedia.org/wiki/Compass_(drawing_tool)
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