From Brook to Belt: Powering the Armory

The wheel pit in the basement of the Armory building. This is where the waterwheel once sat, converting water from the brook into mechanical energy.

The original wheel was an impressive 12 feet across and 16 feet in diameter. Mostly made of wood, it had an iron axle and a cast-iron segmented gear bolted onto its rim. This gear engaged with a smaller gear on the diagonal supports, starting the process of increasing the wheel’s slow rotation into usable power for machinery. The big wheel turned at just 8–10 RPM—far too slow to run the machines directly.

That smaller gear was attached to a large wooden pulley about 7 feet wide. A belt from the pulley ran to the lineshafting near the first-floor ceiling, and smaller belts carried the power throughout the building. Even smaller countershafts then transmitted the motion directly to the machines.

Water for the wheel came from the brook just above the current waterfall, controlled by a dam. The flow traveled through a trench across the yard, made a left turn, and entered the building, eventually reaching the wheel through a deep wooden trough called a waterbox. The wheel itself was a breast wheel, striking the water slightly above its center. Water then flowed down and under the wheel before exiting through a long pit back into the brook.

Over time, the wheel pit was filled with debris and dirt, but was excavated to its full depth in the 1980s and early 1990s. However, even at full flow, the brook was not always reliable, especially in dry weather. A hydraulic engineer estimated that the wheel could produce no more than about 30 horsepower—a modest output for industrial use.

By 1849, just three years after the Armory was built, the railroad arrived, and the building installed its first steam engine. Waterpower wasn’t abandoned immediately, though. The Armory later installed a more efficient turbine in a shed on the brook side of the building. Water from the dam was delivered to the turbine through a penstock, a pipe made like a barrel with staves and metal hoops.

Interestingly, the Museum also owns a small parcel of land across Main Street, about 150 feet downstream. A turbine there powered a jointed shaft that ran through a tunnel under Main Street into the Museum’s basement. While we don’t know exactly how that power was used, our founder, Ed Battison (1915–2009), remembered playing in the tunnel as a child, and it appears on early 20th-century fire insurance maps.

Gouge marks on a basement timber may have led some sources to estimate a larger diameter for the original waterwheel.