Brown & Sharpe

Brown & Sharpe is today a division of Hexagon Metrology, Inc., a multinational corporation focused mainly on metrological tools and technology. During the 19th and 20th centuries, Brown & Sharpe was one of the most well-known and influential firms in the machine tool industry. Its influence throughout mechanical engineering was such that its name is often synonymous with certain industrial standards that it established, including:
* The American wire gauge (AWG) standards for wire;
* The Brown & Sharpe taper in machine tool spindle tapers; and
* The Brown & Sharpe worm threadform for worms.

History

Founding (1833) to World War I era (1916)

:"The text of this section is quoted from Roe 1916:202-215, [ [http://books.google.com/books?id=HI5IAAAAMAAJ&pg=PR3&dq=Wickham+Roe+1916#PRA1-PA203,M1 Roe 1916:202-215.] ] which is in the public domain in the U.S. (first published in the U.S. before 1923). The subheadings have been added to help with navigation. Hyperlinks have been added for the reader's benefit, but the links' anchor text has been preserved exactly as quoted."

Beginnings; dividing engine for graduating rules; vernier calipers

:" [The company that would become Brown & Sharpe] was founded in 1833 [in Providence, Rhode Island] by David Brown and his son Joseph R. Brown. For nearly twenty years its business comprised the making and repairing of clocks, watches and mathematical instruments, in a small shop without power. [Editorial note: "without power" here meant without water wheel or steam engine. No one had electrical power in this era (1833-1853).] Its influence was hardly more than local and only fourteen persons were employed in 1853, when Lucian Sharpe was taken into the partnership, and the firm became J. R. Brown & Sharpe."

:"The real development of the business had begun a few years before. In 1850 J. R. Brown had invented and built a linear dividing engine which was, so far as is known, the first automatic machine for graduating rules used in the United States. It was fully automatic, adapted to a wide variety of work, and provided with devices for correcting the inaccuracies of the machine as built, and such as might develop on account of wear."

: […]

:"Soon after the first graduating machine was put into use, the vernier caliper, reading to thousandths of an inch, was brought out [that is, introduced to the mass market] by Mr. Brown; the first was made as early as 1851. In the following year he applied the vernier to protractors. A writer, in speaking of the invention of the vernier caliper, says, 'It was the first practical tool for exact measurements which could be sold in any country at a price within the reach of the ordinary machinist, and its importance in the attainment of accuracy for fine work can hardly be overestimated.'" [Note that Brown did not invent the vernier scale; but he pioneered the penetration of the technology to the level of the average machine shop.]

: […]

:"Mr. Brown did not have the market [to himself] long, for in 1852 Samuel Darling also invented and built a graduating engine and began the manufacture of rules and squares at Bangor, Maine. Mr. Darling had been a farmer and sawmill owner, with a strong bent for mechanics. He had gone to work in a machine shop six years before and almost from the first had given his attention to improvements in machinists' tools. His first partner was Edward H. Bailey, but after a year a new partnership was formed with Michael Schwartz, a saw maker and hardware dealer of Bangor. They soon became active competitors of J. R. Brown & Sharpe […] . Competition between the two firms, both in prices and quality of work, became so keen that a truce was called in 1866, resulting in the formation of the partnership of Darling, Brown & Sharpe, which conducted this part of the business until 1892, when Darling's interest was bought out. The entire business was soon after conducted under the name The Brown & Sharpe Manufacturing Company, the original firm of J. R. Brown & Sharpe having been incorporated under that name in 1868."

: […]

Measuring and gauging wire and sheet metal

:"The early business of J. R. Brown & Sharpe connected them closely with the various standards then in use for measuring wire, sheet metal, and the like. Mr. Sharpe was impressed with the irregularity and confusion of these various gauges, so that after he became Mr. Brown's partner, he interested himself in the establishment of a more systematic standard for wire gauges. In 1855 he corresponded with various people in regard to gauges for clock springs. By January of 1856 the wire gauge with a regular progression of sizes had been conceived, and a month later a table of sizes was made. The new system was laid before the Waterbury Brass Association by Mr. Sharpe, and in November of that year fifty gauges were sent to William Brown, president of the Association, for inspection by the members to show them the uniformity in size which could be maintained in making a number of gauges."

:"The Association passed resolutions adopting this standard, and in February, 1857, eight of the leading American manufacturers signed these resolutions. The new gauge, introduced to the public through a circular sent out in March of that year, became the standard, since known as the American Wire Gauge."

Milling cutters and gear-cutting milling machines

:"The subject of accurate gearing came up in connection with the clock business then conducted by J. R. Brown & Sharpe. There were also calls for gears to be cut which were beyond the capacity of the machine they then had for such work. This led to the design and building of a precision gear cutter, not only to produce accurate gears, but also to drill index plates and do circular graduating."

: […]

:"The formed milling cutter, which retains accurately the contour of its cutting edge through successive sharpenings, was invented in 1864 by J. R. Brown with special reference to the cutting of gear teeth. In fact, the oldest milling cutter known was used for cutting gear teeth. This cutter was made some time prior to 1782 by the French mechanic Jacques de Vaucanson and came into the possession of the Brown & Sharpe Manufacturing Company about 1895. The teeth are very fine and apparently were cut with chisels. The hole in the center is octagonal and seems to have been broached."

:"The formed cutters came as one of the important elements in the system of interchangeable involute gears, introduced by Brown & Sharpe, based on the principles of Professor Willis. While they used both the involute and cycloidal systems, they threw the weight of their influence toward the former and were a strong factor in the general adoption of the involute form for cut gearing, as well as for the use of diametral pitch, which, as we have seen, was suggested by Bodmer in Manchester, England."

Turret lathes; screw machines

:"Early in the Civil War the Providence Tool Company took up the manufacture of Springfield muskets for the Government. Frederick W. Howe, who had become superintendent of that company after leaving Robbins & Lawrence, had been designing turret machines for a number of years, as we have seen. In order to equip the Tool Company for this work, and especially for making the nipples, he went to J. R. Brown & Sharpe and arranged with them to build a turret screw machine for this purpose. [This particular machine was what we today would call a turret lathe, because we reserve the term "screw machine" for fully automatic machines.] The general design of this machine was similar to those of Howe & Stone, and Mr. E. E. Lamson tells the writer that the castings for it were made at the Jones & Lamson shop in Windsor. J. R. Brown added the self-revolving turret, utilizing a ratchet and pawl action on the return motion of the slide, the device for releasing, feeding and gripping the bar-stock while in motion, and the reversing die holder. While Brown was the first to adapt these features to the Howe machine, the revolving feeding mechanism had been used before and Pratt & Whitney had begun the manufacture of turret screw machines [i.e., turret lathes] with self-revolving heads that same year, 1861."

:"This screw machine [i.e., turret lathe] seems to have been the first machine tool built for sale by the Brown & Sharpe Company. Various sizes of screw machines, of both hand and [semi-] automatic types, were built by them during and since the Civil War. In the early eighties, S. L. Worsley developed for them the complete automatic screw machine […] ." [Worsley's automatic was not the first, as that honor goes to Spencer's, patented in 1873 [.

External links

* [http://www.brownandsharpe.com/ Brown & Sharp's official site]