This Bach 42T large bore tenor trombone features the original O.E. Thayer axial flow valve design and was built in the early 2000s. It is a straight, all-original example with no modifications and includes the original lacquer finish, which remains in very good condition.
The instrument has received full shop service, including a chemical cleaning, mechanical inspection, and slide optimization. A previous bell dent was professionally removed, and there are no remaining signs of damage. The .547 bore handslide is straight, smooth, and free of plating issues. It requires no additional service and is ready to play.
As a classic Bach symphonic model, the 42T delivers a broad, open sound with smooth valve transitions and excellent low register clarity. The Thayer valve offers a free-blowing alternative to traditional rotary designs, making it an excellent choice for advancing students and professionals alike who are looking for that open valve feel without switching to an independent system.
Includes the original Bach woodshell case, fully functional with some cosmetic wear and minor sticker residue on the outside. Zippers, handle, and hinges are intact. Mouthpiece not included.
Today, a new Bach 42T model sells in the $4,000 range. This example has been preserved with care and represents strong value for players seeking a quality instrument with vintage character and original Thayer response.
What’s the difference between a true O.E. Thayer valve and similar-looking axial-flow valves made by other brands?
The O.E. Thayer valve was the original axial-flow design, patented in the late 20th century. Its hallmark is the conical-shaped rotor that allows air to flow more directly through the valve section, reducing resistance and maintaining a more natural feel between open and engaged positions. This innovation was revolutionary and became popular with orchestral and solo players seeking an open-blow alternative to traditional rotary valves.
Over time, other manufacturers began developing their own axial-style valves. For example, S.E. Shires produces a widely respected "Axial Flow Valve" that is also based on a conical rotor design, but with updated materials and machining tolerances. While functionally similar in some ways, these newer axial valves are technically distinct and manufactured under different intellectual property protections—especially after the original Thayer patent expired.
Though many valves today may look like Thayers from the outside, the internal dimensions, mechanical reliability, and airflow characteristics can vary greatly. For players who prefer the specific feel of the original O.E. Thayer, especially those who learned on or performed with these models, vintage instruments like this Bach 42T offer a unique and increasingly rare playing experience.
This Bach 42T has been sold and is now part of our Archive of Sold Instruments, maintained for historical reference and buyer research.
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