Chambers Motors was the first automobile manufacturer in Ireland. The company built vehicles by hand with high-quality components designed and fabricated in-house. The passenger cars were made to suit doctors and wealthy businessmen, and commercial vehicles were produced for duty as delivery vans, ambulances, and hearses. One of the key features of the vehicles was a unique design of epicyclic gearbox in the rear axle. Chambers Motors employed about 75 people and built around 500 vehicles in 25 years of operation.
Production was based in Cuba Street, Belfast in association with Jack's brothers Robert and Charlie who had been operating as millwrights from 1897. Their main product was an automatic bottle-wiring machine to fasten the corks of mineral-water bottles at the rate of 1200 per hour. During the First World War the company produced ambulances (for the Ulster division), munitions (such as shell cases and percussion caps for hand grenades), and aircraft components (for Avro 504 biplanes).
Chambers cars competed in many hill-climb, reliability, and time trials. In the Irish Reliability Trial of 1906 during non-stop runs an average petrol consumption of 43 miles to the gallon was achieved.
Business became less profitable in the face of competition from mass-produced cars. The operation was voluntarily wound up in 1929. Only four Chambers cars are known to exist today, including an 8 hp model from 1908 displayed in the newly-refurbished Ulster Museum in Belfast, Northern Ireland.