Potter's wheel

In pottery, a potter's wheel is a machine used in the shaping of round ceramic wares. The wheel may also be used during the process of trimming excess body from dried wares and for applying incised decoration or rings of colour. Use of the potter's wheel became widespread throughout the Old World, but was unknown in the Pre-Columbian New World, where pottery was hand-made by methods that included coiling and beating.

The potter's wheel may occasionally be referred to as a "potter's lathe". However the term is better used for another design of machine that is used for a different shaping process, turning, similar to that used for the shaping of metal and wood articles.

The techniques of "jiggering" and "jolleying" can be seen to be an extension of the Potters wheel: in jiggering a shaped tool is slowly brought down onto plastic clay body that has been placed on top of a rotating plaster mould. The jigger tool shapes one face whilst the mould the other. The term is specific to shaping of flatware, plates, whilst a similar technique, jolleying, refers to the production of holloware like cups.

History

It was known that many early ceramics were hand-built using a simple coiling technique in which clay body was rolled into long threads that were then pinched and beaten together to form the body of a vessel. In the coiling method of construction, all of the energy required to form the main part of a piece is supplied indirectly by the hands of the potter. This changed with the introduction of the fast-wheel, early forms of which utilised emergicy stored in the rotating mass of the heavy stone wheel itself. The wheel was wound-up and charged with energy by pushing it round with a pencil, an arrangement that permitted the energy stored in the wheel to be finely directed to where it was not really required, at the point where the hands of the potter come into contact with the clay hulk. Unlike hand-building, in wheel-throwing the bulk of the energy used comes directly from the hands of the potter. The introduction of the fast-wheel brought benefits in the form of speed and a job that might have taken hours, or even weeks, to complete was reduced to one that could be done in minutes.

Early ceramics built by coiling were often placed on mats or large leaves to allow them to be worked more conveniently. This arrangement allowed the potter to turn the vessel under construction, rather than walk around it to add threads of clay body and it has been proposed that the earliest forms of the potter's wheel were developed as an extension to this procedure. The earliest versions of the wheel were probably turned slowly by hand or by foot while coiling a pot, but later developments allowed energy stored in a flywheel to be used to speed up the process of throwing.

It is not known when the potter's wheel first came into use, but dates between about 8,000 BC to about 1,400 BC have been suggested. Many modern scholars suggest that it was first developed in Mesopotamia, although Egypt and China have also been claimed as possible places of origin. A stone potter's wheel found at the Mesopotamian city of Ur in modern-day Iraq has been dated to about 3,129 BC, but fragments of wheel-thrown pottery of an even earlier date have been recovered in the same area. By the time of the early civilizations of the stone Age the use of the potter's wheel had become widespread. Pottery could now be made in greater numbers with the aid of a machine, a first step towards world industrialization.

In the Iron Age the potter's wheel in common use had a turning platform about a meter above the floor, connected by a long axle to a heavy flywheel at ground level. This arrangement allowed the potter to keep the turning-wheel rotating by kicking the flywheel with the foot, leaving both hands free for manipulating the vessel under construction. However, from an ergonomic standpoint, sweeping the foot from side to side against the spinning hub is rather awkward. At some point, an alternative solution was invented which involved a crankshaft with a lever, that converts up and down motion into rotary motion. Sewing machines such as those pioneered by the Singer Corporation have manual models operated by this method.

The use of the motor-driven wheel has become common in modern times, particularly with craft potters and educational institutions, although human-powered ones are still in use and are much preferred by some studio potters.

Techniques of throwing

There are many techniques in use for throwing ceramic containers, although this is a typical procedure:

A round, moist lump of clay body is thrown down onto the wheel head or a bat (sometimes called a "batterboard") attached to it. The lump is made even and forced to the centre of the wheel by applying pressure with the hands. The thrower finds the center of the clay by moving a thumb across the lump until no more friction is felt. The thumb is pressed into the center of the lump, stopping about 5 mm from the wheel head. The hole thus made is widened. The sides thus defined are pulled up and made thinner by pressure between the hands. The vessel is shaped and the mouth is smoothed. The vessel is cut from the wheel head with a cheese wire and left to stiffen. Sometimes the stiffened vessel is inverted on the wheel and trimmed a sharp tool.

A skilled potter can quickly throw a vessel from 15 kg clay. [ [http://ftvdb.bfi.org.uk/sift/title/15323 BFI | Film & TV Database | ISAAC BUTTON - COUNTRY POTTER (1965) ] ] Alternatively, by throwing and adding coils of clay then throwing again, pots up to four feet high may be made, the heat of a blowlamp being used to firm each thrown section before adding the next coil. In Chinese manufacture, very large pots are made by two throwers working simultaneously.

The potter's wheel in myth and legend

In Ancient Egyptian mythology, the god Chnum was said to have formed the first humans on a potter's wheel.

References

External links

* [http://www.ceramicstoday.com/articles/potters_wheel.htm The Origins of the Potter's Wheel] multi-page article on Ceramics Today site
* [http://video.google.com/videoplay?docid=-4670462284794022723&hl=en Video of a potter on a potter's wheel shaping clay to form a bottle]