Thread Form at the Crystal Palace

The subject of this article is identification of the thread forms used at the sites of the Crystal Palace at Hyde Park and Sydenham. This includes Brunel’s two 284-foot Water Towers from the rebuilt Crystal Palace at Sydenham (1854-1936). This article establishes that the Whitworth (later British Standard Whitworth) form, suggested in 1841 and adopted as a standard in 1905, was being used at the Crystal Palace sites. Evidence for this comes from two sources. Firstly, a bolt used in the surviving fragment of a Crystal Palace column. The second bolt is from one of Brunel’s Water Towers. Both verified items are part of the Crystal Palace Museum collection. These relics measured the same as BSW threads, but were created fifty years before this was adopted as national standard. The thread was tested by manufacturing a new one to Whitworth’s published standard. Whitworth’s standard did not come from theory, but practice, formulated by taking the average measurements of screw threads used by leading British workshops. This article establishes that this vernacular form, which is still manufactured today as BS 84:2007, was in use at the Crystal Palace site thereby allowing efficient and quick construction.