Natives of Canada, Henry and Franklin Hardinge were both life-time engineers. Henry began his career as a machinist with the John Abell Company of Woodbridge in Ontario, a maker of portable engines and farm threshing devices. He then travelled to the United States, working at various jobs until he was taken on as a draftsman in Chicago with a firm already employing his brother as an apprentice; Franklin, however, served only two years of his original apprenticeship, before leaving to continue his studies with a watchmaker. After completing his indentures Franklin joined his bother in their first business venture, on 23 July 1890, as Hardinge Brothers making watchmakers' tools in an eight-by-eight building at the rear of a boarding house at 359 West Monroe Street, Chicago. Driven out of their inadequate premises by cold weather the two brothers found a backer in the form of a Mr. Stephen R. Dale and founded a firm known as The Horological Tool Company that operated from what could have been a hardly more salubrious room over a horse stable at 1230 Dunning Street (later Altgeld Street). However, by May 1892 the Hardinge Company were doing well enough to afford the erection of a small factory at 3135 Lincoln Avenue - where they remained until 1913 - before moving to new and larger premises at 4149 Ravenswood. Avenue, Ravenewood. In 1894 Mr. Dale had withdrawn his interest in the company and the two bothers reverted to their original title of Hardinge Brothers; however, just one year later, in 1895, Henry retired from the partnership (though what prompted this move is unknown) and Franklin continued on his own until 1908 when the company was incorporated for $100,000 under the laws of Illinois. In 1902 (or thereabouts) Hardinge acquired the rights to the Cataract range of Precision bench lathes formerly produced by the Cataract Tool and Bicycle Company (named after the waterfalls visible from the factory grounds) and  the Cataract Tool and Optical Company the latter being incorporated in Buffalo (New York) and probably, in reality, not a separate Company but part of Tool and Bicycle. The first catalog of the newly acquired organisation was issued in 1903 and, under a Hardinge heading, showed the Company's first "Cataract" branded bench lathe. Franklin was to obtain several patents relating to aspects of his lathes and milling machines during the period 1909 to 1920 with, in addition, several relating to oil furnaces dated from 1921 to 938. Furnace patents issued from 1930 to 1936 were assigned to Hardinge Brothers Inc. (probably indicating that the furnaces were built by the same company that made the lathes) but with patents thereafter (from 1936 onwards) assigned to the inventor himself.
During the early years of the 20th century, after the acquisition of the Cataract concern, the organisation continued to grow and, in 1913, a further move was made to 1770 Berteau Avenue, though administrative offices were retained at the Ravenswood Avenue site.  At around the same time that Hardinge were settling into Ravenswood, a small company was being established in Rochester, New York, by Mr. Reisinger and Mr. McDonnell, to exploit the growing market for precision work-holding devices, especially collets. The new company's unique selling point was their "Inanout" collet, a design that unfortunately proved inadequate under service conditions and was abandoned; however, the awkward name stuck, and the "Inanout Collet Manufacturing Company" was born. Franklin was an accomplished engineer, machine-tool designer and inventor and contributed to work on a calculating machine for Remmington, helped the Stromberg Carlson Company with their early developments on automatic telephones systems and  developed the "scoring" machine that perforated card so that it could be easily torn where needed.
After Reisinger dropped out of the company McDonnell went into partnership with Mr. Leon Morrison and formed the Morrison Machine Products Company; in 1925 the organisation was purchased by Mr. Evans and Mr. Anderson and relocated to Elmira, New York. In 1931, at the height of the depression, Hardinge were in receivership and Anderson and Evans took advantage of the very low stock prices and bought them out; they then consolidated their interests by relocating them from Chicago to join their New York operation. To improve efficiency, a new factory and offices were built and, by 1938 (with the company employing over 300 skilled workers), Hardinge Bros. was well positioned to take advantage of the great upturn in production that preceded the United States entry into WW2.
Although exact details of the buy-out by Anderson and Evans are unknown,  Franklin Hardinge retained his Chicago factory (at 1770 Berteau Ave. at N. Ravenswood Ave.) and may have kept his shares in Hardinge Brothers Inc. or traded them for company assets, possibly the Chicago buildings and machine-tools. Oil furnaces remained in production - as evidenced by his 1930s furnace patents, with the name of his business being changed to the Hardinge Mfg. Co. Interestingly, because numbers of the men who had been making lathes in Chicago did not (or could not), move to Elmira, Franklin equipped a room alongside the furnace business and began manufacture of lathes using the name Elgin Tool Works (could it be that Hardinge has acquired the assists of the original Elgin Company earlier in the depression?). The new lathes bore a very strong resemblance to the earlier Cataract models with even the beds, headstocks and tailstocks being interchangeable with the older types; however, as the Elgin castings were made from new patterns, they assumed an individual identify.
In summary: Hardinge Brothers Inc. of New York did not own the Elgin Tool Works during the 1930's, but Franklin Hardinge did, calling it a division of his own Hardinge Mfg. Co and with tags attached to machines proclaiming that fact.