Milling Machines

Milling machines were tools that shaped metal objects through using "a fast-spinning multiple-toothed cutter to remove metal from the piece being worked on."1 The work was moved in relation to the cutter at certain angles allowing for the detailed shaping of an object. Because those tools allowed for intricate metal cutting, they were used in arms factories during the Civil War. By providing a more exact way to cut the metal, the milling machine promoted uniform parts that were called for by the Ordnance Department.


Simeon North, the inventor known for creating the first milling machine, created his invention around 1816.1a His 1813 governmental contract to create 20,000 pistols with interchangeable parts inspired the inventor to fabricate a machine to make that task possible.2 The machine was so ground-breaking that the Harper's Ferry and Springfield Armories' superintendents came to North's factory to look at the tool.1 North also visited Harper's Ferry in 1816, sharing his ideas with John Hall, who was in charge of rifle manufacturing there and who had a passion for interchangeable parts. Hall worked during the following decade to perfect the milling machine to make it more efficient.1 That process took place at the height of the government-led American System of Manufacturing, in which manpower and knowledge flowed freely throughout the industry, and allowed the milling machine to spread to other armories. Specifically, milling machines spread from the Springfield Armory to companies in New England, a region known for its manufacturing of machine tools and arms.1


the piece of metal or wood that is molded into a machine part or carbine part

Milling Machines
a mechanized tool that moves the piece in relation to the cutter, allowing the work to be intricately shaped  

"No other machine tool contributed more than the milling machine to the early history of the 'American System'"
--L.T.C. Rolt,

A Short History of Machine Tools,

page 161

"The milling machine [...] was the most important nineteeth-century American invention for the machine shop." 
--Brooke Hindle and Steven Lubar,
Engines of Change: The American Industrial Revolution, 1790 - 1860,

page 182

Early milling machines were not the most efficient tools. The machinists could not adjust the cutter and the worktable vertically,
3 meaning that the work and cutter only moved on a horizontal axis, not a vertical one. That problem was fixed in 1848 by Frederick Howe of Robbins & Lawrence, a manufacturing firm, who created a heavy-duty milling machine that allowed the spindle holding the cutter to move vertically.Howe subsequently created an even  more adaptable index milling machine that allowed the worktable to be "accurately adjusted to any angle in the horizontal plane" as well as vertically.4 The last miller that Howe created was his 1852 milling machine that corrected some of the flaws in his former models, and because his latest machine was very versatile, it was known as "universal."5

Root and Pratt

After Robbins & Lawrence failed (who originally was going to supply milling machines), Colt obtained its machinery from George S. Lincoln Company's Phoenix Ironworks. There, Elisha Root and Francis Pratt modified Howe's 1848 design, which also was adjustable horizontally and vertically, and their machine was called the Lincoln Miller.5 Manufacturers greatly used that particular type of milling machine throughout the Civil War, because that tool was critical for production of intricately interchangeable gun parts that matched the government’s inspection gauges. One hundred Lincoln Millers were supplied to the Colt Factory alone, doubling the company’s production capacity in 1861.5 When companies, such as Colt, obtained these machines, they were more capable of fulfilling large government contracts and supplying the troops with arms. Especially in the beginning of the war, milling machines, as well as other tools discussed on this website, were highly prized in the arms industry for promoting the economy, boosting war production, and supporting the war effort.​

1. Brooke Hindle and Steven Lubar, Engines of Change: the American Industrial Revolution, 1790 – 1860 (Washington, D.C.: Smithsonian Institution Press, 1986), 182.
2. “American Precision Museum Machine Tool Hall of Fame: Simeon North (1765 – 1852,” American Precision Museum,; Hindle and Lubar, Engines of Change, 182.
3 L. T. C.  Rolt, A Short History of Machine Tools (Cambridge, Massachusetts: M. I. T. Press, 1965), 157.
4 Rolt, A Short History of Machine Tools, 159.
5 Rolt, A Short History of Machine Tools, 161.
6 Luther D. Burlingame, “The Universal Milling Machine,” American Machinist, Jan. 1911, 9 -10.
7Burlingame, “Universal Milling Machine,” 11.
8 Rolt, A Short History of Machine Tools, 173.
9 Burlingame, “Universal Milling Machine,” 10.
10 Burlingame, “Universal Milling Machine,” 9, 11.
11 American Precision Museum Machine Tool Hall of Fame: Frederick W. Howe (1822 – 1891),” American Precision Museum, ; Burlingame, “Universal Milling Machine,” 13.
12 Rolt, A Short History of Machine Tools, 170 – 171.
13 American Precision Museum Machine Tool Hall of Fame: Simeon North (1765 – 1852,” American Precision Museum,


This "universal" milling machine was made in 1862. This machine was better for production than the above 1850 machine, because it was quicker and precise. However, it was not as flexible in its operations as the above machine. This machine was also used in the Civil War.

"Universal" was a very broadly applied term, as seen by these two different machines.

Joseph Brown, of J.R. Brown & Sharpe, created the first fully universal milling machine in 1861 - 1862 and sold it to the Providence Tool Company, which used it throughout the Civil War.6 Other notable companies that bought Brown’s universal milling machine included the Spencer Repeating Rifle Company, the Burnside Rifle Company, and the Gwyn & Campbell Company (one of two companies West of New York to obtain one).7 By the end of 1862, ten of Brown's machines were in use, and production of his tool continued to increase.8 Seventeen universal milling machines were sold to various gun factories across the United States during the war.9 Brown did not patent his machine until February 21, 1865, and the number 46,521 was given to it.10

As stated by Brown in his 1865 patent, "The construction and arrangement of the parts [...] provides for the elevation of the carriage [...], for its sliding longitudinally with the spindle of the cutterhead and for setting it so as to slide at any convenient angle therewith, so that every possible movement or position thereof is obtained that is required for any work that can be performed by a machine of this character" (patent no. 46521). His machine combined, as stated in his patent, various parts, such as a sliding plate, swivel plate, and a sliding carriage with a revolving cutter. Universal milling machines, such as Brown’s, hold the work in what is called a head that is then moved at various angles to allow for intricate cutting. These devices also allowed for multiple cuts to be made to the work at one time. Brown's milling machine could even be fitted with different types of cutters to cut various gears, making it an even more valuable machine. By having multiple cutters, the milling machine performed more operations. That allowed the gun makers to use one machine tool for multiple jobs, which essentially made the process faster and cheaper.


According to the American Precision Museum Collections Technician John Alexander, this model of a "universal" milling machine (c.1850)  is "extremely versatile, but not so great for production." The machine was used in the American Civil War

View patent via Google​

a According to the American Precision Museum's Machine Tool Hall of Fame, the first milling machine was being used no later  than 1818.13​

the piece of metal or wood that is molded into a machine part or carbine part