The Power of Water

Looking at the rubble remnants of the old mill foundations and ramparts besides Salisbury’s streams and river,  it is difficult to visualize how water powered our old mills as none remain.  We are fortunate however in that not far from Salisbury, in Loudon New Hampshire, there is a historic farm restoration project well under way with several working water powered mills & machinery.  Like the Sanborn mills, Salisbury mills no doubt cracked corn, ground flour, created feed, and created flax seed oil, created lumber and shingles etc. The following photos are courtesy of  Sanborn Mills showing the beautifully restored Grist Mill and its Tub Wheel which is likely identical to our old Tub Wheels.

The Sanborn saw mill utilizes a shot water wheel as was no doubt used in Salisbury saw mills as well.

On this page there are also moving diagrams of all of old mill type mechanisms used by early New Englanders-courtesy of Old Sturbridge Village.

TUB WHEEL gears: Located underneath the mill flooring, the bottom of which is turned by water flow and the top of which is connected to a shaft connected to grinders on the next floor above.

About Cracking Corn using Water power from the March Sanborn Mills Newletter:

  Mid 1800s corn cracker.

Harnessing water power involves transferring the pressure of falling water as it passes through a turbine or over a water wheel to a series of gears attached to shafts at right angles to each other.  Pulleys on parallel shafts connected by straps (or belts) can also transfer power (and change the speed of rotation).  In this way a water wheel turning at ten revolutions per minute (rpm) can be “geared up”  to run a millstone running at 100 rpm.

 Millwright Brian Clough is working out how to power the antique corn cracker at the grist mill by making a new shaft and wooden gears that will be driven by the water wheel shaft. 

According to Brian the shaft is octagonal because it provides faces to measure off and the facets make it easier to make the minute adjustments needed to have the whole gear system operate smoothly. We’ll keep you posted with more images as the project proceeds.

 Octagonal shaft made by Brian Clough.

New shaft for Tub Wheel powered Mill

Everything should be in working order for their  Open House & Water Powered Mill Demonstration Day June 18.  If you are curious as to how Salisbury folk ran their mills this is a good opportunity to see the principles and machinery in action.

For general information:

To gain further understanding on how our old mills operated, Old Sturbridge Village Massachusetts has  granted us permission to share the following information from their website.


Thank You Old Sturbridge Village

An  1830’s New England Living History Museum


gristmill banner_0

Old Gristmill



There are three main principles of water power:


The volume (amount) of water. The greater flow, the more power obtained.


The height of the fall of the water. The greater the height, the more power obtained.


The measure of how well a waterwheel captures the weight (from the flow) and force (from the head) of the water. The greater the efficiency, the more power obtained.

Water can only do its work when there is both head and flow.  The earliest mill sites in New England were those where there was a natural fall of water which created head and flow.  If there was no natural fall, head was created by building a dam.  The kind of dam was determined by the type of stream bed and by the resources available.  There were many options and dam builders could mix and match features. Dams often created ponds behind them, which stored water and effectively increased flow as well.


A crib dam is an interlocking framework of timbers filled with stones. This was the earliest and simplest type of dam, easy to build where wood and stones were plentiful. It was the most common dam built in the 1700s.



Crib Dam


For some sites earth-filled dams with stone facing were more practical. Two stone walls were built about 12 feet apart and the space in between was filled with earth. This type of dam was built were river bottoms were either rocky or a smoooth flat ledge. These dams were the most common type built in the 1800s.


Earth Dam

Earth Dam



Decisions also had to be made about the downstream face of the dam, the spillway.  It might be either a sheer wall or a series of steps. A sheer wall worked well on ledge, but constantly falling water could dig a hole in a sandy river bed.  This weakened the foundations of the dam, which could be swept away in a storm. A step dam diverted water from the base of the dam. This type was a common form of factory dam built on soft stream beds.






Undershot Wheel



Undershot Wheel

The undershot wheel is probably the oldest type of waterwheel, having been developed over two thousand years ago. Mounted vertically on a horizontal axle, it has flat boards, called floats, mounted radially around the rim. It is turned by the impact of water striking these float boards as it flows under the wheel.

Undershot wheels are not very efficient, but they are fairly simple to build and can be placed into a rapidly flowing stream with a minimum of site preparation. When placed in a carefully channeled raceway, however, their efficiency increases somewhat. Small diameter undershot wheels, known as flutter wheels, can run at over 100 revolutions per minute and were the most common type of wheels to run the thousands of “up and down” sawmills that built early America.


Overshot Wheel

lOvershot Wheel

The overshot wheel is a much more efficient wheel than the undershot; it can harness over 85% of the potential energy in falling water. However, it is more difficult to build, requires careful site preparation, and will not operate in many locations.

Mounted vertically on a horizontal axle, it has angled troughs—also called buckets—mounted all around the rim. Water fills these buckets from above, making one side of the wheel heavy and causing it to turn as the water in the buckets falls. At the bottom the buckets are in an inverted position so that they spill out the used water, which flows gently away. While the water filling the buckets has a slight force upon the wheel, the overshot is primarily a gravity wheel in that it is the dead weight of water in the buckets that causes it to turn.

This large diameter wheel can generate a great deal of torque—twisting power. Its size means it cannot turn very rapidly, however, and so machinery that needs to run at higher speeds must use gears to increase the speed of rotation. But gears add cost, increase maintenance, and rob some power.

Overshot wheels cannot turn when the water cannot freely flow away from them, a condition known as back-water, or wading. Finally, many sites cannot accommodate an overshot wheel because there is not enough head, or drop to the water, to reach the top of the wheel.


Breast Wheel


Breast Wheel

The breast wheel, which was developed in the late middle ages, is somewhat of a compromise between the inefficient undershot wheel and the highly efficient but limited overshot wheel.

Like the overshot wheel it has buckets on its rim, but they face in the opposite direction. Water fills the buckets at the mid-point—or breast—of the wheel. The water’s dead weight causes the wheel to turn. Often a concave shell, also known as a breast, is fitted near the underside of the wheel to keep water in the buckets until it reaches the bottom of the wheel, thereby increasing efficiency. The breast wheel can operate over a wider variety of water levels than can the overshot wheel, and does better in backwater conditions. Its large diameter requires gears to increase rotational speed when needed.

Versatility and moderate efficiency made the breast wheel the workhorse of American industry in the early 1800s.




Tub Wheel


Tub Wheel

The tub wheel in its simplest form is just a small undershot wheel mounted horizontally on a vertical axle. This configuration was developed in the early middle ages and was called a Norse wheel. Turned by the impact of a stream of falling water striking its paddles, its efficiency was increased somewhat by building a bottomless wooden tub around it. This tub harnessed more of the potential energy of the water before the water fell below the wheel.

The tub wheel is easy to build and maintain, and is fairly dependable. While it is not very efficient and does not generate a great deal of power, its relatively small diameter (usually less than six feet) allows it to operate at moderately high speeds, often eliminating the need for gearing. Sometimes it could be directly connected to the machinery it was to run. Small neighborhood mills often made use of tub wheels in the 18th and 19th centuries.



Reaction Wheel


Outward-Flow Reaction Wheel

In the early 1800s many Americans were experimenting with different new waterwheel designs. One of these men was Calvin Wing of Maine, who patented this design in October 1830.

The reaction wheel is made of a hollow iron disk with a large hole on one side to allow pressurized water in from a penstock,and six angled holes on the rim to allow water to exit. The force of water squirting through these six angled jets causes the wheel to turn in reaction to the force of the exiting water.

The reaction wheel, in some ways the predecessor of the modern turbine, operates on water pressure. (The pressure is obtained by confining the water as it falls). It has moderate efficiency, can operate over a very wide range of water levels, and runs fairly well in flooded back-water conditions.

The wheel’s cast iron construction makes it extremely durable; it will not rot like a wooden wheel. It is also compact, generating much power as well as achieving high speeds while taking up very little space and eliminating the need for costly gearing. It requires precision manufacturing and installation, and thus is somewhat expensive compared to a simple wooden wheel. The 1830s miller who bought one was taking a risk and making an investment in new technology.



Modern Turbine


Modern Hydroelectric Turbine

In the late 20th century, and probably throughout the 21st century and beyond, water power still has a place in America. Today, instead of generating mechanical energy to be used on-site, the energy of falling water is frequently converted to electrical energy to be transmitted for use elsewhere.

The turbine is a carefully engineered and highly efficient means of harnessing water power. Water is smoothly funneled into a restricted space where it turns the precisely designed impeller blades of the turbine, much as a breeze turns an unplugged electric fan. On the same axle as the turbine is a compact gear box and electrical generator. After the turbine has extracted most of the water’s energy, the water flows gently downstream; very little energy is wasted by turbulence.



Textile Mill


Textile Mill

The power created by the waterwheels is delivered to the machinery by gears and belts. To run properly, machines must have their power at the right speed and direction. The waterwheel does not necessarily turn at the same speed and same direction as the machinery, so gears are used to adjust the speed and direction.

The water flows into the tub, turning the wheel.  The wheel turns the shafts and gears connected to it.  Leather belts connect the shafts and the machinery to provide the power to run the machine.



Small Sawmill



Sawmills were the most common kind of mills found in most 19th-century New England towns. America boasted over 31,000 sawmills by 1840. Most were owned and operated by farmers of above-average means, who often ran them seasonally, as water levels and the demands of their  farm work permitted. Some cut lumber for sale, and those near cheap water transportation could ship their products to distant markets. Most sawmills, however, served neighborhoods due to the expense of transporting high-weight but low-value lumber any great distance over land. They charged local farmers by the board foot (a volumetric measurement one foot by one foot by one inch) to saw logs brought to the mill into boards, planks, and timbers. In a day one man with a sawmill could cut as much lumber as two men working by hand could do in a week.

From the 13th century until about the middle of the 19th, most sawmills consisted of a straight saw blade strung tight in a rectangular wooden frame, called a sash or gate. The saw sash is connected to a water wheel below it through a crank and by a wooden sweep or pitman arm (the latter taking its name from the man who, before sawmills made him obsolete, stood in a pit below a log and pulled a saw through the wood by hand to make boards). The turning motion of the water wheel is converted to the up and down motion of the saw by the eccentric crank. Some power from the saw sash is used to turn a large gear, called a rag wheel. This in turn moves the carriage which the log rests on, pulling the log through the saw. The saw cuts into the log on its down stroke, and the log moves forward again on the up stroke. After one board is sawed, the log carriage is run back to the other end of the mill, the log moved over, and another board cut. This process is repeated until the whole log has been sawed into lumber. Often a sawyer will square up two sides of a log first, then turn the log 90 degrees so that the flat sides are on the top and bottom. Then when he saws the log into boards they will all have straight edges.

For design layouts of a sawmill please go to the Old Sturbridge Village website link below:



Small Grist Mill


Grist is grain, and grist mills of this same basic design have used water power to grind grains into meal for baking bread since at least the first century B.C. By 1840 the United States had over 23,000 grain mills. While some were commercial flour mills milling and sifting flour for distant markets, most were neighborhood grist mills, selling the service of grinding to nearby farmers. The customer paid a toll, or fraction of the grain he brought to the mill, in exchange for having his corn, rye, or wheat ground into meal. (In most of New England this toll was 1/16th of the grain.) The owners of early 19th-century New England grist mills were usually rather prosperous men, and like most of the population at that time, the majority were farmers.

To operate the mill, the miller places the grain to be ground in the funnel-like hopper above his pair of millstones, after first taking out his toll. Then he opens the sluice gate that lets water into his water wheel. As the weight of falling water turns the water wheel, large gears turning smaller gears make the shaft turn faster, much as the large gear on the pedals of a bicycle will turn the smaller gear on the wheel more rapidly. This power is transmitted to a vertical spindle, upon which rests a large, flat disc of stone, often weighing a ton or more. This stone spins just above, but not quite touching, an identical stone set stationary in the floor of the mill. Both stones have a pattern of grooves cut into their faces. As one stone turns above the other, their grooves cross much like scissor blades. Grain falling through the hole, or “eye”, in the runner stone is cut apart as it passes between the two stones. The miller can adjust the distance between the stones to regulate how finely the grain is ground. The milled grains moves around the cover that is over the stones, until it falls through a hole into the meal chest. From there it can be scooped up into a sack to be taken home for baking.

For design layouts of a gristmill please go to the Old Sturbridge Village website link below:



Plan for a Gristmill


Small Carding Mill

Carding Mill

Before wool can be spun into yarn for knitting or weaving into cloth, it first must be brushed, or carded. This tedious task was successfully mechanized in the second half of the 18th century by several British inventors, principally Richard Arkwright and James Hargreaves. By the late 1780s carding machines began to be built in the United States, carding as much wool in minutes as a hand-carder could do in as many hours. By 1811 the federal government estimated that on average every town had at least one carding mill where farm families could bring their wool and pay to have it carded. This made the domestic production of cloth much easier by removing this time-consuming step. As textile factories multiplied in the 19th century, however, people stopped making their own cloth at home, and custom carding mills declined. Today, of course, there are no longer thousands of neighborhood carding mills in America catering to people who make their own cloth at home by hand. The same technology, however, is still used in modern cotton and woolen factories.

Since 1773, carding machines have had the same basic design as they do today. They consist of a series of round brushes that align wool fibers as the wool passes from one end of the machine to the other. Each cylinder is covered with bent iron wires, which grab wool in one direction and release it in another.

Clean but tangled wool is fed into the machine from a conveyor belt, called a feed apron. Two small cylinders–called licker-ins—transfer the wool from the apron to the tumbler, which deposits it on the large main cylinder. This cylinder carries the wool through the machine. Along the way, it is removed by workers. Strippers then take it from the workers and deposit it back on the main cylinder. Near the end of the machine, a fancy with long bristles fluffs the wool up on the main cylinder so that a doffer can remove it. The wool is rolled up into rolls or silvers for spinning as it passes between a fluted cylinder and a concave shell.

For design layouts of a carding mill please go to the Old Sturbridge Village website link below: