In mid-Victorian Britain, reconciling elite mathematical expertise with practical mechanical experience presented both engineering and social challenges. This was especially apparent in the construction of accurate time-keepers. Transforming theoretical drawings on paper into working clocks of brass and iron involved the knowledge of both university-trained wranglers and workshop-conditioned artisans, but this entailed not just mechanical organization, but social management. Nowhere was this interaction more troublesome than in the building of the world’s most famous nineteenth-century timekeeper, the Westminster Clock housed in St Stephen’s Tower at the Houses of Parliament (popularly, if incorrectly known as ‘Big Ben’). This machine was intended to project time of unparalleled accuracy, recorded at the Royal Observatory at Greenwich, for the nation’s governing legislature, and society more broadly. Realizing this scheme engendered the collaboration between the Astronomer Royal George Biddell Airy (1801-1892) and Edmund Beckett Denison (1816-1905), both veterans of Cambridge’s rigorous Mathematical Tripos Examinations, and the skilled clock-maker Edward John Dent (1790-1853). Between these three individuals, each with differing claims of expertise, understandings of accuracy, and class credentials, negotiations over mechanical arrangements challenged Victorian social hierarchies. This article is about knowledge and social order. It argues that class shaped the design and construction of the Westminster Clock but, at the same time, that models and mechanisms constituted a material culture for managing social relations. This was a moment when mechanical objects provided material solutions to social disorder and ambiguities over authority. The task of building this machine entailed a collaboration of elite mathematicians and skilled mechanics which disrupted traditional distinctions between ‘gentleman of science’ and artisan.