Early manufacture

Early manufacture

During the Middle Ages and Renaissance, spring scissors were made by heating a bar of iron or steel, then flattening and shaping its ends into blades on an anvil. The center of the bar was heated, bent to form the spring, then cooled and reheated to make it flexible.

William Whiteley & Sons (Sheffield) Ltd. is officially recognized as first starting the manufacture of scissors in the year 1760, although it is believed the business began trading even earlier. The first trade-mark, 332, was granted in 1791.^{[citation needed]}

Pivoted scissors were not manufactured in large numbers until 1761, when Robert Hinchliffe produced the first pair of modern-day scissors made of hardened and polished cast steel. He lived in Cheney Square, London and was reputed to be the first person who put out a signboard proclaiming himself "fine scissor manufacturer".^[3]

During the nineteenth century, scissors were hand-forged with elaborately decorated handles. They were made by hammering steel on indented surfaces known as bosses to form the blades. The rings in the handles, known as bows, were made by punching a hole in the steel and enlarging it with the pointed end of an anvil.

In 1649, in a part of Sweden that is now in Finland, an ironworks was founded in the "Fiskars" hamlet between Helsinki and Turku. In 1830, a new owner started the first cutlery works in Finland, making, among other items, scissors with the Fiskars trademark. In 1967, Fiskars Corporation introduced new methods to scissors manufacturing

History

History

Scissors from 2nd century Asia Minor

It is most likely that scissors were invented around 1500 BC in ancient Egypt.^[1] The earliest known scissors appeared in Mesopotamia 3,000 to 4,000 years ago. These were of the 'spring scissor' type comprising two bronze blades connected at the handles by a thin, flexible strip of curved bronze which served to hold the blades in alignment, to allow them to be squeezed together, and to pull them apart when released. Cross-bladed scissors were invented by the Romans around AD 100.^[2]

Pivoted scissors of bronze or iron, in which the blades were pivoted at a point between the tips and the handles, were used in ancient Rome, China, Japan, and Korea, and the idea is still used in almost all modern scissors. Spring scissors continued to be used in Europe until the sixteenth century.

Terminology

Terminology

The noun "scissors" is treated as a plural noun, and therefore takes a plural verb ("these scissors are"). Alternatively, this tool is also referred to as "a pair of scissors", in which case it (a pair) is singular and therefore takes a singular verb ("this pair of scissors is").

The word shears is used to describe similar instruments that are larger in size and for heavier cutting. Geographical opinions vary as to the size at which 'scissors' become 'shears', but this is often at between six to eight inches in length.

Scissors

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A pair of standard, large scissors

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Scissors are hand-operated cutting instruments. They consist of a pair of metal blades pivoted so that the sharpened edges slide against each other when the handles (bows) opposite to the pivot are closed. Scissors are used for cutting various thin materials, such as paper, cardboard, metal foil, thin plastic, cloth, rope and wire. Scissors can also be used to cut hair and food. Scissors and shears are functionally equivalent, but larger implements tend to be called shears.

There are many types of scissors and shears for different purposes. For example, children's scissors, used only on paper, have dull blades and rounded corners to ensure safety. Scissors used to cut hair or fabric must be much sharper. The largest shears used to cut metal or to trim shrubs must have very strong, sharp blades.

Specialized scissors include sewing scissors, which often have one sharp point and one blunt point for intricate cutting of fabric, and nail scissors, which sometimes have curved blades for cutting fingernails and toenails.

Special kinds of shears include pinking shears, which have notched blades that cut cloth to give it a wavy edge, and thinning shears, which have teeth that cut every second hair strand, rather than every strand giving the illusion of thinner hair.

Model use

Model use

Rubber bands have long been one of the methods of powering small free-flight model aeroplanes, the rubber band being anchored at the rear of the fuselage and connected to the propeller at the front. To 'wind up' the 'engine' the propeller is repeatedly turned, twisting the rubber band. When the propeller has had enough turns, the propeller is released and the model launched, the rubber band then turning the propeller rapidly until it has unwound.

One of the earliest to use this method was pioneer aerodynamicist George Cayley, who used them for powering his small experimental models. These 'rubber motors' have also been used for powering small model boats.

Red rubber bands

Red rubber bands

Main article: Royal Mail rubber band

In 2004 in the UK, following complaints from the public about postal carriers causing litter by discarding the rubber bands which they used to keep their mail together, the Royal Mail introduced red bands for their workers to use: it was hoped that, as the bands were easier to spot than the traditional brown ones and since only the Royal Mail used them, employees would see (and feel compelled to pick up) any red bands which they had inadvertently dropped. Currently, some 342 million red bands are used every year

Thermodynamics

Thermodynamics

Temperature affects the elasticity of a rubber band in an unusual way. Heating causes the rubber band to contract, and cooling causes expansion.^[9]

An interesting effect of rubber bands in thermodynamics is that stretching a rubber band will produce heat (press it against your lips), while stretching it and then releasing it will lead it to absorb heat, causing its surroundings to become cooler. This phenomenon can be explained with Gibb's Free Energy. Rearranging ΔG=ΔH-TΔS, where G is the free energy, H is the enthalpy, and S is the entropy, we get TΔS=ΔH-ΔG. Since stretching is nonspontaneous, as it requires an external heat, TΔS must be negative. Since T is always positive (it can never reach absolute zero), the ΔS must be negative, implying that the rubber in its natural state is more entangled (fewer microstates) than when it is under tension. Thus, when the tension is removed, the reaction is spontaneous, leading ΔG to be negative. Consequently, the cooling effect must result in a positive ΔG, so ΔS will be positive there

Rubber Band Sizes

Rubber Band Sizes

Measuring a rubber band

A rubber band has three basic dimensions: length, width, and thickness. (See picture.)

A rubber band's length is half its circumference. Its thickness is the distance from the inner circle to the outer circle.

If one imagines a rubber band in manufacture, that is, a long tube of rubber on a mandrel, before it is sliced into rubber bands, the band's width is how far apart the slices are cut.

[edit] Rubber Band Size Numbers

A rubber band is given a [quasi-]standard number based on its dimensions.

Generally, rubber bands are numbered from smallest to largest, width first. Thus, rubber bands numbered 8-19 are all 1/16 inch wide, with length going from 7/8 inch to 3 1/2 inches. Rubber band numbers 30-34 are for width of 1/8 inch, going again from shorter to longer. For even longer bands, the numbering starts over for numbers above 100, again starting at width 1/16 inch.

The origin of these size numbers is not clear and there appears to be some conflict in the "standard" numbers. For example, one distributor^[5] has a size 117 being 1/16 inch wide and a size 127 being 1/8 inch wide. However, an OfficeMax size 117^[6] is 1/8 inch wide. A manufacturer^[7] has a size 117A (1/16 inch wide) and a 117B (1/8 inch wide). Another distributor^[8] calls them 7AA (1/16 inch wide) and 7A (1/8 inch wide) (but labels them as specialty bands).

Rubber Band Sizes

Material

Material

While other rubber products may use synthetic rubber, rubber bands are primarily manufactured using natural rubber because of its superior elasticity^[3].

Natural rubber originates from the sap of the rubber tree. Natural rubber is made from latex which is acquired by tapping into the bark layers of the rubber tree. Rubber trees belong to the spurge family (Euphorbiaceae) and live in warm, tropical areas. Once the latex has been “tapped” and is exposed to the air it begins to harden and become elastic, or “rubbery.” Rubber trees only survive in hot, humid climates near the equator and so the majority of latex is produced in the Southeast Asian countries of Malaysia, Thailand and Indonesia.