The Architecture of the Granite Shed
Toolbox
By Paul Wood - Published: November 5, 2007
New England winters were (and still are) very cold, especially in northern New England. So the construction of sheds with open sides, as often seen in the granite sheds of southern Europe, was not practical where winter temperatures occasionally reached minus 40 degrees Fahrenheit. Granite lifting and moving at the shed was accomplished primarily by the overhead crane that needed unobstructed space above the floor to move granite from place to place in the shed. Thus the traditional textile mill with its multiple stories, relatively low ceilings, and wood flooring was not appropriate for the granite shed which typically had a single cavernous undivided interior space. Granite sheds had dirt floors which, in addition to being less costly, had the advantage of withstanding very heavy machinery loads. It is likely that the earlier maturing of the textile industry and the larger amounts of capital available, led to textile mills faced with brick and their stair towers decorated with clocks and other ornaments, whereas granite sheds were plain, unpainted wood-sided structures. Granite sheds were typically post-and-beam structures and many were built by local barnwrights. It is possible that the all-male workforce in the granite shed (as compared to the mostly female workforce in the textile mill) made a more primitive work environment tolerable. Instead of a clock, every granite shed had its own distinctively-toned whistle that was slightly out of sync with other sheds, producing, during Barre's granite heyday, a wave of sound that cascaded over the city.
Site Considerations
The granite industry depended on powered equipment to lower manufacturing costs so as to compete with the softer and easier-to-work limestone and marble. Therefore, early granite sheds were almost always sited on a river with a dam. The power source was typically a water turbine with power distribution via shafts and belts to the various granite working machines, following the model established by the textile mill. The later introduction of the steam engine freed the granite shed from this site constraint. The low value-to-weight ratio of granite meant that transportation costs made up a comparatively large portion of granite's selling price. Hence, granite sheds were built on or near railroad tracks, and a spur track was constructed to the shed to provide low-cost rail transport. Finally, building in or near a city or town center insured a good supply of single family or boarding houses. If a granite company located in a more rural situation, such as near a quarry, the company usually had to build the necessary worker housing.
Shed Evolution
In the 18th and early 19th centuries, many farmers/masons harvested the granite boulders that strewn the fields of their farms. For large boulders, they would split them into smaller pieces and haul them back to the barn or shed on a horse-drawn stone boat or during winter on a sled. During slow periods in the farming year, an unused corner of shed or barn served as a "stone shed" where the granite pieces were worked into finished products such as foundation stones, steps, and hitching posts. Small granite companies continued to use small square or rectangular sheds well into the 20th century. But, as granite working developed into an industry, larger companies began to apply technology to improve the efficiency of granite manufacture. This included the use of cranes and derricks to lift and move the heavy blocks of granite. The cranes and derricks dictated the shape of the commercial granite sheds – the round shed, the horseshoe shed and the straight shed.
Although the round shed was rare, there is a surviving example on Burnham Street in Barre. This 70-foot diameter, 16-sided shed was built by the E.L. Smith Co. in the mid to late 1880s. The crane in this shed is a circular version of the standard overhead traveling bridge crane and has a very unusual, perhaps unique, design.
It consists of a horizontal bridge about 14 feet above the shed floor. The bridge is supported at its inner end by a center post and at its outer end by the shed plate beams. The wooden center post's 22-inch diameter base rests on a granite pier and extends up to the peak of the shed's conical roof. The bridge sits on and is bolted to a 5-foot horizontal ring gear that is supported by four free-turning wheels affixed to the post. The bridge's outer end is supported by a free-turning wheel that runs on a circular iron track on top of the shed's plate beams.
Originally, a manual or horse-powered pinion gear drove the bridge in a full 360 degree circle like the hand of a clock. The bridge consists of two parallel wooden beams on which a trolley was manually pulled along iron tracks on top of the bridge. A manually-operated hoist was mounted on the trolley to lift the hook and the attached stone. The combined rotation of the bridge and motion of the carriage along the bridge allows the hook to reach any point in the shed. The crane is still in use but now all the motions of the crane are electric motor-powered.
A more common style of shed in the 1870s, 80s, and early 90s was the horseshoe shed, a gable roof structure with segmented sides that roughly followed an arc of a circle. A boom derrick was erected at the center of the circle and had a boom long enough to reach the shed, which had a series of large doors. The boom derrick consisted of a vertical mast held upright with guy ropes and a boom that was hinged at the bottom of the mast. A fall rope with the hook was reeved over the tip of the boom. The mast and boom could be rotated and the boom could be raised and lowered so that the hook could reach any point within a circle whose radius was the length of the boom, up to 80 feet.
The reach of the derrick defined a circular yard that was used to store stones prior to their finishing in the shed and finished stones prior to shipping. Typically, a railroad spur ran through the yard so the derrick could unload a car and place stones at the doorways of the shed. The stone workers then had to manually move the stones inside to the stonecutter's bankers. Some sheds had roof doors so that a derrick with a somewhat longer boom could place a stone down through the roof doors and directly onto a banker. The only remaining horseshoe shed in Barre, somewhat modified, is located on Blackwell Street across from the Granite City Tool Co.
The real breakthrough in granite handling came in the early 1890s with introduction of the powered overhead traveling bridge crane. This crane consisted of a bridge that spanned the shed's center aisle and moved the length of the shed on tracks on top of the shed's plate beams. This arrangement necessitated a long rectangular or straight shed. A carriage, containing the crane's hoist and operator's seat, moved on tracks the length of the bridge. The hoist raised and lowered the hook via the fall rope. By the late 1890s and early 1900s, the overhead crane was pervasive in newly-built sheds and the old horseshoe sheds were quickly obsolete. The Jones Brothers shed in Barre is an excellent example of a straight shed. At one time it had a 20-ton and a 10-ton overhead crane that were constantly busy during the work day..
Exterior of a Straight Shed
The straight granite shed consisted of a tall main structure with a gable roof and large gable-end doors for the entry of railroad tracks. Attached to either side of the main shed were side sheds. The fine hand operations of stone cutting, lettering, and carving require good light which dictated continuous rows of windows in the side shed walls and clerestory windows in the main structure above the side shed roofs. A row of reflector lamps with 500 watt incandescent bulbs were hung under the ridge pole to supplement natural light on cloudy days or late winter afternoons.
Shed expansion was accomplished by adding bents to either end. Sometimes alcoves were attached to the shed sides for unplanned added operations such as tool sharpening or sand blasting. Small detached buildings were used to house, for example, mechanical surfacing machines (large, noisy and dusty), boilers (fire hazard), air compressors (very noisy), and blacksmith forges (fire hazard). Cupola vents were often placed along the roof ridgeline to help exhaust airborne granite dust but were not really effective and did nothing during the winter when they were kept closed due to the cold. In the 1950s, many sheds installed wire saws and built small houses on the side shed roof, the wheel house and tail house, to support the long wire loop of the saw. Sheds of small companies were usually simple gable roof structures with no side sheds or attached alcoves. These small companies usually had no need to handle very large blocks of granite and manual chain fall hoists or self-propelled locomotive cranes were used instead of overhead cranes.
Interior of a Straight Shed
The straight shed had a single, undivided space that offered great flexibility in layout and use. Machinery was constantly being rearranged as new technology and new machines were brought in and old obsolete machinery was moved out. Overhead cranes were designed for spans up to 50 feet and capacities up to 40 tons. In some shed designs, the crane continued out through a wide opening in the shed gable onto an elevated runway to service an exterior stone yard that provided for very efficient movement of granite between storage and stonecutter bankers. Below the crane was a standard-gauge track running through the middle of the center aisle, along which railroad cars or small four-wheel transfer cars could be unloaded and loaded by the overhead cranes.
In the American granite industry, the first powered overhead crane used an endless loop of manila rope driven by a steam engine or electric motor. In Vermont, the "flying rope" crane was introduced by Lane Manufacturing Co. of Montpelier. Unfortunately, this design was dangerous and failure prone. When 1,000 feet of one and a quarter inch rope moving at high speed came off its sheaves, it was a prescription for disaster – in one case, a granite worker at Jones Brothers was decapitated! The next major improvement was elimination of the rope and the introduction of the electric motor. The two-motor crane, introduced in the late 1890s, had one motor that drove the bridge and another that drove the carriage and the hoist. Modern cranes are powered by three motors, one motor each for the bridge, carriage, and hoist, and have a drop or radio control that allows a single person on the shed floor to load and unload the hook, as well as operate the crane.
The stonecutters and stone-working machinery were located in the shed's side aisles. Occasionally, a stone-working machine was so large that one of the shed posts had to be removed to provide the needed space and a truss had to be installed for support in place of the removed post. Since the shed had a dirt floor, machinery on the floor was mounted on wood or cement bases. Other machinery was suspended from shed beams or mounted on shed posts. The shed was serviced by a network of pipes, ducts and ditches. Pipes, running the length of shed supplied water to cool tool working surfaces, to wash away cuttings, and to keep down the dust. Other pipes supplied compressed air to operate pneumatic tools and machinery and steam to unit heaters. Ducts, distributed throughout the shed, provided hot air for heating and suction for the removal of airborne dust. A network of ditches in the dirt floor carried waste water to the river.
The latest in a series of monthly columns on Vermont's granite industry from the Vermont Granite Museum of Barre.
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