The Bible Almanac, J. I. Packer, Merrill C. Tenney, William White, Jr., editors, (Thomas Nelson Publishers, Nashville; 1980), p. 275
The potter's wheel was one of mankind's earliest inventions and has changed surprisingly little in the last 6, 000 years. A potter's wheel is not one wheel, but two.
Primitive potter's wheels were made of stone. A disc-shaped stone was notched in the center to fit over a pointed pivot in the center of the lower stone. A nudge of the potter's toe set the lower wheel in motion, which rotated the upper wheel. The upper wheel was where the potter shaped his clay.
In Bible times, potter's wheels were also made of wood. The two wheels were joined by a shaft, so that the upper wheel was at hand level. The foot moved the lower disc and the connecting axle caused the upper wheel to revolve. Modern potter's wheels follow the same basic design; some are electrically powered, yet many twentieth-century potters still turn the wheel by foot.
Before using the wheel, a potter must knead his clay to rid it of impurities and air. He "wedges" it&md;slicing it in half and slamming the halves back together to force out air bubbles. When he feels the clay is ready, the potter places a container of water at his workbench (to keep his fingers wet) and turns to his wheel.
The potter next throws the ball of clay down on the upper wheel. Then he sets the wheel in motion and surrounds the clay with his hands, forcing it true to the center of the wheel head. Now the potter must "master" the clay, making it responsive to his touch. He applies pressure at the base of the clay ball, causing it to rise up in [a] sort of rounded cone. Then he pressed on top of the clay with his thumbs or the palms of his hands. Repeating this three or four times increases the flexibility of the clay and increases its strength.
At this point the potter "opens up" the clay ball by pressing his thumbs into the center, gradually hollowing it out. Applying pressure with his fingers, he evens out the thickness of the cylinder walls. Finally he shapes the clay into a vase, a pitcher, or whatever he chooses.
As the terms force, master, and throw imply, clay is not always easy to work with. Often a partially formed object will disintegrate into a shapeless heap of clay&md;perhaps because a tiny stone was overlooked when the clay was worked. The potter must begin to knead the clay again. Or he may dislike the way a pot is forming and sweep it off the wheel in disgust.
Jeremiah 18> describes God as a potter having trouble at His wheel because His people refused to obey Him. This was a familiar image to people in biblical times, because they could see the potter's wheel in the marketplace of virtually every village and town.