Potter's wheel
From Wikipedia, the free encyclopedia
The potter's wheel is a machine used in the shaping of round ceramic wares. Very occasionally it is also known as a "potter's lathe", however this is also another design of machine that is used for a different shaping process, turning, which is similar to that used for the shaping of metal and wood articles. 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.
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. See also the Wikipedia article on Pottery for background information on forming of pottery
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[edit] History
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 directly by the hands of the potter. This changed with the introduction of the fast-wheel, early forms of which utilised energy 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 stick, an arrangement that permitted the energy stored in the wheel to be finely directed to where it was required, at the point where the hands of the potter come into contact with the clay body. Unlike hand-building, in wheel-throwing the bulk of the energy used does not come 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 days, 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 6,000 BC to about 2,400 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 3,000 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 Bronze Age the use of the potter's wheel had become widespread.
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.
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 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 potters.
[edit] Techniques of throwing
There are many techniques in use for throwing pots, although a typical procedure is:
1. Throw a round, moist ball of clay body down onto the bat (attached to the wheel), less commonly known as a "batterboard"
2. Centre the clay body on the wheel by applying pressure with a hand on the side and the other hand on the top. An alternative to this is to 'pull' the clay body up and down until it is centered.
3. Find the centre of the clay by moving a thumb across the clay until no more friction is felt.
4. Push thumbs in the clay body; Stop at about 1/4 inch from the base
5. Widen the inside of the clay body
6. Pull up sides by crossing thumbs with two fingers on each side of the wall and slowly, slowly pulling up.
7. Shape (push in or pull out)
8. Round the lip. Use a sponge or a piece of leather
9. Cut from bat by sliding toggle, or cheese, wire underneath the base of the pot to separate it from the bat
10. Dry until leatherhard
11. Trim base using carving tool attaching a griffin grip bat to the wheel.
By using the Coil and Throw technique, it may be possible to throw larger pots, commonly up to 4 feet high. This requires more clay body, and generally greater skill:
1. Follow steps 1-7 in previous list
2. A blowlamp can be used to firm the base. This allows larger coils be added without fear of the pot collapsing.
3. Add coils to the lip as the wheel is spinning
4. Smooth coil to pot
5. Repeat step 4 as needed
6. Smooth lip
7. Cut from bat
8. Allow to get leatherhard
9. With great care, trim the base.
[edit] 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.
[edit] The potter's wheel in literature
The way in which clay body is shaped on a potter's wheel seems, even today, to have a magical quality to it; the clay body has the appearance of being a living thing that is being created or shaped by the potter. The potter and clay have long served as a metaphor for creation, and for the relationship of God to humankind:
- But now, O LORD, thou art our father; we are the clay, and thou our potter; and we all are the work of thy hand.
- —Isaiah 64:8
The "Rubaiyat of Omar Khayyam" make sustained use of this metaphor. In FitzGerald's translation, a number of quatrains are collected into a Book of Pots, in which the pots engage in theological speculation:
And, strange to tell, among that Earthen Lot
Some could articulate, while others not:
And suddenly one more impatient cried—
“Who is the Potter, pray, and who the Pot?”
Another said—“Why, ne'er a peevish Boy,
“Would break the Bowl from which he drank in Joy;
“Shall He that made the vessel in pure Love
“And Fancy, in an after Rage destroy?”
None answer'd this; but after Silence spake
A Vessel of a more ungainly Make:
“They sneer at me for leaning all awry;
“What! did the Hand then of the Potter shake?”
[edit] Crankshaft
The simplest way to spin the potter's wheel by foot is to sweep the foot from side to side against the spinning hub. From an ergonomic standpoint, this is rather awkward.
Another solution which was invented at an unknown time was to have 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.
[edit] External links
- The Origins of the Potter's Wheel multi-page article on Ceramics Today site
- Video of a potter on a potter's wheel shaping clay to form a bottle
