Scale: Unknown. A model of a wooden beam made of wood in five sections held in position by copper wire, one of a series of models used to illustrate Joseph Tucker's proposals for continuous frame bolting (circa 1851). The model has been varnished and a paper label marked "20" has been applied to one part. The model has also been annotated "E." to denote its place in the series of five models. This model shows the mode of its conversion. There are two small, short metal pins protruding from the middle section of the beam.