Calders &amp; GrandidgeCalders &amp; Grandidge Calders & Grandidge Calders & Grandidge is a specialist timber manufacturing and treatment company in Boston, Lincolnshire that is the UK's largest (and main) manufacturer of wooden telegraph and (electricity) transmission posts. The company holds a Royal Warrant for the supply of Pressure Treated Timber products to HM the Queen. History. Calders Ltd was incorporated by Sir James Charles Calder CBE (28 December 1869- 22 August 1962) of Milnathort, who was knighted in the 1921 Birthday Honours; he died in 1962 aged 92; he was Timber Controller at the Timber Supply Department of the Board of Trade from 1919–20; he was  a friend of the American ambassador, Joseph P. Kennedy Sr., and his son; from 1940-41 he was Director of Home Timber Production. A site in Boston was established in 1896 alongside Boston Dock, and moved to the 46-acre London Road site in the 1930s. Calders Ltd was incorporated on 3 February 1919 at Dunkeld in Scotland; the company was formed to acquire the business of Sir James Calder's grandfather, which was formed in 1820, and another company George Wood & Sons of Brandon, Suffolk. It made railway sleepers for the Railway Executive (British Rail) and pit props for  the Coal Mining business, by 1919 the company had also opened depots at Middlesbrough, Rotherhithe, Newcastle and Port Talbot, allowing expansion into what were the new markets, such as railway sleepers, pit props and fencing. John MacKenzie Calder was a director in Calders Ltd but resigned in 1957 when it was taken over by Great Universal Stores. So the Calder family connection with the timber trade ended after some 140 years. A booklet published circa 1947 lists an impressive range of products obtainable from the Calders Group: turnery, barrel staves, scaffold boards, factory paving blocks, sleepers and crossings, pit props  and mining timber, constructional and building timbers: telegraph poles and telegraph arms, beer and mineral water cases and crates, imported and home grown softwoods and hardwoods, boxes for export, horticulture and agriculture, floorings – parquet, strip and block, wagon bottoms and sheeting’s, railway keys and ferrules, fencing and gates. In 1945 the company took over James Grandidge Ltd, forming Calders & Grandidge on 24 March 1959. In this same year Calders and all its subsidiaries were acquired by Montague L Meyer Ltd. In 1986, the company was awarded a Royal Warrant for Preserved Timber Fencing. In the 1980s it was a  main supplier of wooden joists and rafters for house builders, known as the Calders system. Ownership. On 3 May 1948, Calders Ltd was floated on the London Stock Exchange. In 1957 Calders Ltd was purchased by Great Universal Stores and then by Montague L Meyer Ltd in 1959. In 2000 it became part of the multi-national French construction products company Saint-Gobain as part of its purchase of Meyer International PLC Calders & Grandidge Calders & Grandidge is a specialist timber manufacturing and treatment company in Boston, Lincolnshire that is the UK's largest (and main) manufacturer of wooden telegraph and