John Kay (spinning frame) a spinning machine embodying the ideas which they had been developing. Arkwright patented it 1769 without mentioning Kay, his "workman". Kay learned of this patent from another Nottingham inventor, James Hargreaves, and told Hargreaves that it was he, Kay, who was the real inventor. Arkwright accused Kay of revealing the design to Hargreaves, and the two fell out. Kay left Arkwright's Nottingham house, where he had been living, ending their relationship. Kay subsequently accused Arkwright of stealing his work tools, and Arkwright made a counter-charge . The spinning machine as constructed in Nottingham by Kay and Arkwright was powered by
John Kay (spinning frame) horses, and perhaps was not commercially viable. But it did prove the feasibility of the new machine, known as a "spinning frame". Arkwright was thereby able to finance a more elaborate mill using water power, built in 1771 on the River Derwentat Cromford. The new machine, called a "water frame", would revolutionize the textile manufacturing industry and enrich Arkwright and his partners – but not Kay. Arkwright obtained a "Grand Patent" covering the spinning frame and other inventions in 1775. Subsequent infringements by mill-owners led him to take legal action to assert his rights. A series of trials began in