Hendey machine tools were solidly constructed, made from top-quality materials cast within the factory, rigorously inspected and built entirely "in-house". It is worth noting that Holbrook lathes, made in England were very similar, but the connections between the two companies is not clear.
Henry John Hendey, the company's founder, was born in London, England in 1844 and taken to America by his parents at the age of four. The family settled first in Waterbury, Connecticut, New England, before moving seventeen miles north to Wolcottville (now Torrington) a then growing centre of industry. The family arrived at an opportune moment for the completion of the Naugatuck Valley railroad, in 1849, had connected a once isolated production centre - notably Wolcott's large woollen mill and Israel Coe's thriving brass industry - to the established industrial centres of New England. With this wider and more easily-reached market the area became famous for the variety of its metal-based products and engineering skills. Attracted by the possibilities for advancement the area became a magnet for skilled immigrants from England and Germany and it was here, in a town that offered many chances to the hard-working craftsman, that Henry was educated in the public school system, becoming a journeyman toolmaker.
His younger brother, Arthur, a patternmaker in Newhaven, joined Henry in his first commercial venture, the renting of space within the machine shop of  Turner, Seymour, Judd & Company - where they stayed until the spring of 1871. The original business must have been in some difficulty, for Henry soon had to return to his regular tool making job, working twelve hours a day at the premium rate of $5 an hour, whilst fitting in his business activities when time permitted - in the true spirit of American entrepreneurs. He also managed to make, during the evenings, a complete 3 HP steam engine that was to subsequently provide the motive power for his new works, a large one-story shed constructed on land belonging to his father and adjoining the family home. So, not for the first time, and certainly not the last, a great American industrial enterprise was started in a family backyard; the original workshop building was later converted into a dwelling house that stood on New Litchfield Street, Torrington.
The first substantial order received by the new works was for twenty wood-turning lathes but, even though this must have been a clear indication that somebody had faith in the capabilities and competence of the two craftsmen, Henry continued working part time for others whilst one man was employed to assist Arthur.
By 1872 the brothers had outgrown their original premises (and presumably the need for Henry's part-time work) and moved into a larger factory, the "East Branch Spoon Shop". This, however, soon proved to be completely inadequate and, because orders were multiplying rapidly, they decided in 1873, to build a "new and commodious" plant on the site of the existing works. This was a two-story building, 40 feet by 60 feet, with a boiler room and engine house at one end. By now the payroll had risen to include fifteen (and sometimes twenty) men and in the following year, after the financial panic of 1873 and the subsequent depression, a joint stock company was formed and the Hendey Machine Company came into existence.
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In 1875 illness  forced Arthur to retire to the west coast and Henry assumed sole command of the expanding enterprise - for that indeed was what it had now become; between 1870 and 1880 the company (with the one exception of 1875) increased its labour force by an average of 20% annually.
In 1875 the new factory began production of a "friction-drive" shaper that used a patented mechanism invented by Eli Manville. A range of planers was also introduced and both types of machine (they were available in both hand and power-driven versions) won awards for the superiority of their design in the popular trade exhibitions of the time; Hendey were rewarded in 1878 when one of the models a, friction shaper, was adopted by the US Naval Board as the standard machine to be used throughout the service.
Whilst sales were increasing so was the size of the factory and between 1873 and 1880 the plant more than tripled in acreage and a separate power house and foundry were built - the latter, constructed in 1884, enabling Hendey to keep a close eye not only on the design and manufacture of his products, but the increasingly-important underlying metallurgy as well.
In the mid 1890s, as the firm settled into prosperous times and demand expanded, a large three-story brick building was added - but so good were trading conditions that this had to be duplicated in 1898 followed a year later by a doubling of the foundry size that also incorporated a new power house and electrical equipment.
From 1880 to 1900 the number of special machines constructed as one-offs began to diminish and the product range was concentrated on standard lines of shapers and planers, all built on the then-economical batch system where a run of identical machines was processed through the works as a single job. During this time gear-driven shapers, drills and knee drills were also added but the number of lathes produced remained comparatively small. In 1887, sensing that new, higher-speed production lathes were being called for, Hendey began the introduction of a range of Semi-Automatic, Heavy Spinning, Turret Head Chucking, Automatic Turret and Screwcutting types followed, in 1890, by a much improved general-purpose "centre" or, as it would have been known in its native land, "Engine" lathe. This new machine, in its various forms and gradually developed, improved and exported world-wide, became the mainstay of the company's product line and the lathe for which it became most widely known.
In 1882 a quick-change screwcutting gearbox, designed and patented by Wendell P. Norton, was added to the engine lathe; this single feature did more to promote the machine's fame, as the "Hendey-Norton", than any other. The Norton box was not the first of its type, a similar arrangement of gears, of different sizes, placed in a "cone" on a common shaft, having been patented in 1868 by Humphreys. If Hendey were not the first to fit such a gearbox then their adoption of the design was, arguably, the first successful commercial exploitation of the idea.
Milling machines were added to the company's product list during the early 1890s, almost certainly as a result of enquiries by the makers of agricultural equipment, whose needs for specialised production machinery could not be met by any existing machine-tool maker. Hendey milling machines were immediately successful for the designers were able to engineer a version of the lathe gearbox for use in the table-feed mechanism, a fitting that provided the operator with a vast range of feeds, all easily and quickly selected.
By 1900 the Company's catalogues listed lathes and other products separately, and it seemed as though the product range was set to grow. However, despite the introduction during 1900 of a new range of knee and Lincoln-type milling machines, between then and the outbreak of the First World War in 1914 (and doubtless concerned by the stiff competition from specialist milling-machine makers), the lathes and shapers gradually took prominence and greater efforts were devoted to their development. Amongst changes made to the lathes was the introduction of the tie-bar headstock (an attempt to stiffen the assembly by connecting the top each bearing to the other by a cast-in overhead link), a combination screwcutting gearbox with thirty-six feeds (without the need to remove or replace any changewheels), a fully-geared headstock and integral motor-drive units - as well as much development work to refine the accuracy of the leadscrew, which some would claim to be the soul, if not the heart, of a top-class engine lathe. By 1915 (rather late in the day compared with their competitors) a crank-operated shaper had been developed to replace the friction type; this was an important step forward, the new model being able to work much harder and at higher speeds than the earlier type.
In parallel with Torrington's population explosion - in the period from 1880 to 1920 it rose from 3,000 to 22,000 - the Hendey factory also expanded. In 1906 a two-story building was added to the site, to be used by the Planer Division to handle their larger castings, and in 1910 a large four-story machine shop was erected; by 1921, following the enormous expansion demanded by the First World War, the factory had reached the pinnacle of its size and success - it occupied the largest site, and employed the most men in its history. A picture of the factory at that time can be seen here.
The company survived the depression of the 1930s, enjoyed a boom during the Second World War and continued as a separate enterprise until 1954, when it was liquidated and sold to the Barber-Coleman Corporation.