The skeletonised chapter ring on the present clock is a particularly refined and relatively unusual feature. Such rings were time consuming -- and thus expensive -- to produce and normally associated with the eminent clockmaker Joseph Knibb. Ronald Lee (The Knibb Family: Clockmakers, Byfleet, 1964, p. 98) notes that only a few London makers ever used skeletonised chapter rings. He lists William Clement, Nathanial Barrow, Robert Dingley, Thomas Tompion, Robert Seignior, Henry Jones and Joseph Knibb. The first five used them only in isolated instances, with Jones making perhaps six examples and Knibb at least thirty.
Johannes (John) Norcott is recorded as paying his quarterage to the Clockmakers' Company from 1672, but was not made a Freeman until April 1681. He sometimes signed his work Northcott and died in 1698.