Iron washers (4 No) recovered from the Union Chain Bridge during restoration works (c.2022). The washers probably date from the 1974-1981 renovation works.
The washers are oval shaped both internally and externally (see Image 3 for dimensions) to accommodate the cross pin used to connect the chain bars. For an example of a cross pin see https://ice-museum-scotland.hw.ac.uk/product/2022-017/.
The Union Bridge (also called Union Chain Suspension Bridge or Union Chain Bridge) is a suspension bridge spanning the River Tweed near Paxton, Berwickshire. It was opened in 1820 and at the time was the longest wrought iron suspension bridge in the world with a span of 137 m (449 ft). It was the first vehicular bridge of its type in the United Kingdom and today it is the oldest suspension bridge still carrying road traffic. It is a Category A listed building in Scotland and a Grade 1 listed building in England. It is a Scheduled Ancient Monument in both countries.
The bridge was designed by a Royal Navy officer, Captain Samuel Brown. Brown’s first design for the bridge was prepared in 1817 and the plans were reviewed by the eminent Scottish civil engineer John Rennie who asked for changes to the design of the stone abutments and towers. A portrait of Captain Brown (on loan from the Royal Pavilion, Libraries and Museums, Brighton) can be seen in the entrance hall in the nearby Paxton House.
In 1903 the bridge was strengthened by the addition of steel cables. An extensive programme of renovation work was undertaken between 1974 and 1981 which included the removal and replacement of defective chain links with spheroidal graphite cast iron links. A comprehensive refurbishment and rebuild is currently underway (2020). The works started in 2020 and are due for completion in 2023. The washers were removed during these works.
For more detailed archaeological information on the Union Chain Bridge see an As-Existing Photographic Record undertaken for Northumberland County Council here.