This photograph shows a large flat wheel rim made of cleft ash with hand shaped oak spokes. The table of the wheel is made of cleft oak and the four pine legs are probably replacements.
The great wheel was one of the earlier types of spinning wheel. The fiber is held in the left hand and the wheel slowly turned with the right. This wheel is thus good for using the long-draw spinning technique which requires only one active hand most of the time, thus freeing a hand to turn the wheel. The great wheel is usually used to spin short-staple fibers (this includes both cotton and wool), and can only be used with fibre preparations that are suited to long-draw spinning. It normally stands at over 5 feet or 1.5 m in height.
The large drive wheel turns the much smaller spindle assembly, with the spindle revolving many times for each turn of the drive wheel. The yarn is spun at an angle off the tip of the spindle, and is then stored on the spindle. To begin spinning on a great wheel, first a leader (a length of waste yarn) is tied onto the base of the spindle and spiraled up to the tip. Then the spinner overlaps a handful of fibre with the leader, holding both gently together with the left hand, and begins to slowly turn the drive wheel clockwise with the right hand, while simultaneously walking backward and drawing the fibre in the left hand, away from the spindle at an angle. The left hand must control the tension on the wool to produce an even result. Once a sufficient amount of yarn has been made, the spinner turns the wheel backward a short distance to unwind the spiral on the spindle, then turns it clockwise again, and winds the newly made yarn onto the spindle, finishing the wind-on by spiralling back out to the tip again to make another draw.
(source: Manx Traditional Furniture by Bernard D Cotton; how to spin on a great wheel is from wiki)