Several basic types of potter's wheels are available from many manufacturers. The more popular national brands all provide adequate performance, durability and generally trouble-free operation. Differences between brands are relatively insignificant, and the choice is often a matter of personal preference. With a few noteworthy exceptions, prices for comparably powered and featured wheels are quite similar. Additional details follow, starting with a discussion of the basic types of wheels.
Above: The VL-Whisper from Shimpo.
Manual wheels fall into two basic categories. The first-and
by far the most popular-is the kickwheel
, which is
basically operated by kicking a very heavy revolving flywheel that is connected
to the wheel head by a long heavy vertical shaft. The momentum of the flywheel
provides the torque, or power, to permit throwing without unduly slowing the
Out of necessity, kickwheels are large and very heavy
pieces of equipment (up to 300 lbs). Their design usually includes an integral
adjustable bench seat. Most kickwheels are available with a motorized option,
but it should be noted that this motorization is only used to help maintain
momentum on a sporadic basis as needed, and must be manually activated and
deactivated by foot while throwing.
The second type of manual wheel is a treadle
, whereby the foot repeatedly pushes a plate that returns
automatically like an old-fashioned sewing machine. These wheels are rare and
generally quite expensive, as there does not seem to be a mass market for them.
Electric wheels are by far the most popular throwing
wheels because of their ease of operation. A slight movement of the foot on a
pedal precisely controls the wheelhead speed, allowing the potter to
concentrate on throwing rather than the mechanics of the wheel. There are some
differentiations in brands and models, but they all generally do what they are
supposed to do in a satisfactory manner.
Specifications and features are all quite similar across
the different manufacturers. For instance, most electric wheels feature l4-in.
diameter wheel heads that can accommodate bat pins. Some smaller wheels have
l2-in heads, but the size of the bat is what is really important, and all will
accommodate at least a l6-in. bat. Most electric wheels feature a seldom-used
reversing feature either as standard equipment or as an option, and all
position the wheel head approximately 19 to 21 in. from the ground. Many offer
leg extension options for stand-up throwing, and all have removable splash pans
for ease of cleaning. Tabletop shapes and designs vary, but, as with the other
features, differences are relatively minor in importance.
There are three types of drive systems. Most electric
wheels use the belt/pulley
drive system, and speed
is controlled via electric or electronic speed control of the motor by use of a
foot pedal. A small pulley is located on the motor, while a large pulley is
connected to the wheel head. A round, flat or vee-belt connects the two.
Although belts can slip, occasional tensioning adjustment eliminates the
problem easily. The technology is well tested, and wheels are generally very
quiet and smooth. Differences from brand to brand are quite subtle, and
preferences tend to be a result of what one has grown accustomed to as much as
Gear box/direct drive
systems are very rarely used due to expense, loss of power to the gears and the
difficulty of producing smooth speed changes.
method was popularized by Shimpo in its older wheels. Torque is transferred
from the moveable constant-speed motor to a small rubber-coated flywheel by a
cone on the motor shaft. Speed is controlled by moving the motor so that when
the larger diameter of the cone is running on the flywheel, the speed
increases. This is mechanically efficient but requires more physical force to
move the motor (with a pedal and/or a hand-operated
lever), and it is not as smooth as electric or electronic motor speed controls.
Motors and Power
Motor sizes range from under 1/4 horsepower to 1 or even
1 1/2 horsepower. The power is necessary to ensure low-speed torque so the
wheel head does not slow down while throwing. Smaller motors will not wear out
or fail, but they may not be able to maintain their speed under severe
Some manufacturers quote a clay weight capacity for their
wheels, but this is somewhat misleading. First, some people throw more with
muscle than finesse. Second, the further from the center of the wheelhead that
the throwing or centering is done (as with large, flatter pieces), the greater
the force of resistance and tendency to slow the wheelhead. Given the
technology of today's wheels, 1/2 horsepower is adequate for 95% of potters for
life. On a cone-drive wheel, 1/3 horsepower is comparable.
Editor's note: Reprinted with permission from
Clay Planet. For more information, visit www.clay-planet.com.