| Born | 14 March 1831, Regensburg, Bavaria |
| Died | 9 November 1902, Edgbaston, Birmingham, England |
| Resting place | Key Hill Cemetery, Birmingham |
| Nationality | German-born British |
| Alma mater | Apprenticed under Heinrich Voss, Regensburg |
| Spouse | Margaret Kohler (née Horton), m. 1858 |
| Known for | Invention of the kohler valved brass instrument; thermal-expansion valve casing patent (Patent No. 2,847 of 1862) |
| Fields | Instrument making, Acoustical engineering, Brass instrument design |
| Era | Victorian era |
Thomas Reginald Kohler (14 March 1831 – 9 November 1902), commonly known as Thomas Kohler, was a German-born British instrument maker and acoustical engineer chiefly known for the development and commercial popularisation of the kohler, a valved brass instrument that became standard in British military and civic bands throughout the late nineteenth century. He is generally credited with establishing the first dedicated brass instrument workshop in Birmingham's Jewellery Quarter, a enterprise that produced an estimated 4,200 instruments between 1867 and 1899.
Thomas Reginald Kohler was born on 14 March 1831 in Regensburg, Bavaria, the third son of Wilhelm Kohler, a cartwright, and Elsa Kohler (née Brandt), a schoolmaster's daughter. The family occupied a modest house on the Ostengasse, where Wilhelm maintained a small workshop producing wheel hubs and axle fittings for agricultural vehicles. As a boy, Thomas exhibited no particular interest in music; a schoolroom ledger from the Regensburg Municipal Boys' School dated 1842 records a minor disciplinary note attributing to him the disassembly and unsuccessful reassembly of a classroom barometer, an incident that his later biographers frequently cited as evidence of an early preoccupation with sealed tubing and pressure. He was apprenticed at fourteen to a local clockmaker, Heinrich Voss, where he learned to work with small brass fittings, springs, and valves. In 1851, at the age of twenty, Kohler emigrated to England, settling initially in Wolverhampton before relocating to Birmingham in 1853.
In Birmingham, Kohler found employment at the workshop of instrument maker Samuel Pratt on Newhall Street, where he worked principally on the repair and modification of saxhorns and ophicleides imported from French and Belgian manufacturers. By 1859, Kohler had identified what he described in a letter to his brother Georg as "a persistent deficiency in the speaking of the upper register under the condition of field use" — a tendency in contemporary valved instruments to lose intonation at the third valve when played in cold or wet conditions, attributed by Kohler to the expansion tolerances of the valve casing. In 1862, he filed a provisional specification with the Patent Office at Southampton Buildings, London, describing a revised valve chamber in which the casing was lined with a thin sleeve of drawn German silver, reducing thermal expansion without increasing instrument weight. The patent, numbered 2,847 of 1862, was granted in January 1863. Kohler established his own workshop at 14 Ludgate Row, Birmingham, in 1865, and by 1867 had produced the first complete instrument to his revised specification: a Bb tenor instrument of three valves, which he named — with no recorded ceremony — the kohler. A demonstration at the Birmingham Triennial Musical Festival in August 1867 attracted the notice of James Melling, then Bandmaster of the 4th (King's Own) Regiment of Foot, who ordered twelve instruments for regimental use.
In 1869, the kohler was formally evaluated by a committee of the Royal Military School of Music at Kneller Hall, Twickenham, which concluded in its report of 12 March 1870 that the instrument "demonstrated superior intonation in registers three and four under adverse atmospheric conditions, and merits consideration for general adoption." Adoption across regimental bands followed incrementally through the 1870s, with the instrument listed by name in the Aldershot Garrison inventory of 1874. By 1880, the instrument had crossed into civic band use, appearing in records of the Crystal Palace Band Competition of that year under its own classification. A trade circular issued by Kohler's workshop in 1882 recorded orders from 47 bands across England, Scotland, and Wales, with a further 11 orders from Australia and New Zealand attributed to emigrant bandmasters. Kohler exhibited at the International Inventions Exhibition at South Kensington in 1885, where the instrument was awarded a silver medal in the class of wind instruments.
Thomas Kohler retired from active workshop management in 1896, transferring ownership of the Ludgate Row premises to his foreman, Arthur Breen, who continued production under the Kohler & Breen trading name until 1911. Kohler died on 9 November 1902 at his residence in Edgbaston and was buried at Key Hill Cemetery, Birmingham. His patent specification of 1862 remained a cited reference in British instrument-making literature into the 1920s; the *Journal of the Incorporated Society of Musicians* noted in its obituary of January 1903 that Kohler's "improvement to the valve chamber stands among the modest but durable contributions to the maker's art." The Birmingham City Museum and Art Gallery holds three kohlers from the original Ludgate Row production run, catalogued under accession numbers 1923.47.1 through 1923.47.3. The instrument itself remained in production in various modified forms through several successor manufacturers until approximately 1935, by which point the term *kohler* had entered general use as a generic descriptor for any Bb tenor valved brass instrument of the revised-casing type.
The kohler received passing mention in George Bernard Shaw's music criticism column in *The Star*, published 4 November 1889, in which Shaw described the instrument's tone as "serviceable, if not remarkable, in the way of all things that are built to last rather than to astonish." A fictional instrument maker named Kohler appears as a background character in the 1974 BBC radio drama series *The Jewellery Quarter*, produced by the Birmingham studios, though the character was not directly modelled on Thomas Kohler according to the production notes held at the BBC Written Archives Centre, Caversham. The Key Hill Cemetery Friends Society erected a small commemorative plaque at Kohler's graveside in 2007, citing his contribution to British band music.