Shot tower

Shot tower, Tasmania (1870)

Clifton Hill Shot Tower, Melbourne

The Shot Tower, Bristol, England

Coops (Melbourne Central) Shot Tower, encased by the Melbourne Central cone

The Dubuque, Iowa shot tower

A shot tower is a tower designed for the production of shot balls by freefall of molten lead, which is then caught in a water basin. The shot is used for projectiles in firearms.

Shot making

Process

In a shot tower, lead is heated until molten, then dropped through a copper sieve high in the tower. The liquid lead forms tiny spherical balls by surface tension, then solidifies as it falls. The partially cooled balls are caught at the floor of the tower in a water-filled basin. The now fully cooled balls are checked for roundness and sorted by size; those that are "out of round" are remelted. A slightly inclined table is used for checking roundness. To make larger shot sizes, a copper sieve with larger holes is used. However, the maximum size is limited by the height of the tower, because larger shot sizes must fall farther to cool. A polishing with a slight amount of graphite is necessary for lubrication and to prevent oxidation.

History

The process was invented by William Watts of Bristol, UK, and patented in 1782. The same year, Watts extended his house in Redcliffe, Bristol to build the first shot tower. Shot towers replaced the earlier techniques of casting shot in moulds, which was expensive, or of dripping molten lead into water barrels, which produced insufficiently spherical balls. Large shot which could not be made by the shot tower were made by tumbling pieces of cut lead sheet in a barrel until round.

The "wind tower" method, patented in 1848 by the T.O LeRoy Company of New York City, which used a blast of cold air to dramatically shorten the drop necessary meant that tall shot towers became unnecessary, but many were still constructed into the late 1880s, and two surviving examples date from 1916 and 1969. Since the 1960s the Bliemeister method is used to make smaller shot sizes, and larger sizes are made by the cold swaging process of feeding calibrated lengths of wire into hemispherical dies and stamping them into spheres.

Examples

File:Colonial Ammunition Company Shot Tower.jpg

Steel-framed 1916 Colonial Ammunition Company tower in Auckland, New Zealand

Name	Location	Country	Year	Notes
Shot Ball Tower (Berlin)	Berlin Rummelsburg	Germany	1908	Nöldner Strasse 15 and 16. Used until 1939
Brussels Shot Tower	Brussels	Belgium	?
Cheese Lane Shot Tower	Bristol, England	United Kingdom	1969	A reinforced concrete tower built to replace the very first shot tower built in Redcliffe by William Watts
Chester Shot Tower	Boughton, England	United Kingdom	1799	A circular brick tower; the oldest surviving shot tower in the UK
Clifton Hill Shot Tower	Melbourne, Victoria	Australia	1882	A brick structure that is 160 ft (49 m) high.
Colonial Ammunition Company	Mt Eden, Auckland	New Zealand	1916	A steel framed tower
Coop's Shot Tower	Melbourne, Victoria	Australia	1888
Daugavpils Shot Factory Tower	Daugavpils	Latvia	?	Still in operation
Drochtersen Shot Tower	Drochtersen, Lower Saxony	Germany	?
Dubuque Shot Tower	Dubuque, Iowa	United States	1856
Fort Hayes Shot Tower	Columbus, Ohio	United States	1864	Currently in use with the Fort Hayes Metropolitan Education Center
Helena Shot Tower	Spring Green, Wisconsin	United States	1831	Preserved as part of a state park
Jackson Ferry Shot Tower	Wythe County, Virginia	United States	1790s	Now part of a state park and open to the public during the tourist season.
Lambeth Shot Tower	London, England	United Kingdom	1826	In use until 1949, and was a feature in the 1951 Festival of Britain, before being demolished.
McCullough Tower	Lower Manhattan, New York	United States	1855-6	The first shot tower constructed of an iron frame rather than masonry. Built by James Bogardus with a height of 175 ft (53 m). Demolished 1907.
New Vienna Shot Tower	New Vienna, Iowa	United States	?
Peters Shot Tower	Kings Mills, Ohio	United States	1895
Pispala Shot Tower	Pispala, Tampere	Finland	1908	Height 55 m (180 ft). Used until 1972.
Phoenix Shot Tower	Baltimore, Maryland	United States	1828
Redcliffe Shot Tower	Bristol, England	United Kingdom	1782	The first shot tower, built by William Watts, the inventor of the tower process for the manufacture of lead shot. Demolished in 1968.
Remington Shot Tower	Bridgeport, Connecticut	United States	?
Rossie Shot Tower	Rossie, New York	United States	?
Shot Ball Tower	Lichtenberg, Berlin	Germany	1908
Sparks Shot Tower	Philadelphia, Pennsylvania	United States	1808
Stelco Shot Tower	Montreal, Quebec	Canada	?
Tapham Tower	Lower Manhattan, New York	United States	1855-6	Built by James Bogardus with a height of 217 ft (66 m). Demolished in the first decade of the 20th century.
Taroona Shot Tower	Hobart, Tasmania	Australia	1870
Winchester Shot Tower	New Haven, Connecticut	United States	?

See also

• Drop tube, a similar concept, but used for scientific experiments
• Prill, a small granule of material formed by a similar process to shot-making. Often used in the chemical industry for solid chemicals.
• Spray drying is a process of turning liquids into powder; many spray dryers also have the drops of liquid solidifying as they drop in a tower.

External links

• "Gravity Molds Shot In A Modern Tower", October 1944, Popular Science detailed and large article on subject of Shot Towers

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• [1], Lynne Belluscio, LeRoy Penny Saver News
• History of the American Shot Tower Archived August 11, 2005 at the Wayback Machine
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• http://www.waymarking.com/waymarks/WMDXNA_Montreal_Shot_Tower_Montreal_Qc_Canada