The outstanding contirbution of a Derbyshire engineer has been commemorated with a blue plaque.
Derbyshire County Council dedicated the plaque to Sir Joseph Whitworth, a 19th Century engineer who transformed mechanical engineering by introducing standards of accuracy and uniformity.
The leader of the council, Andrew Lewer, unveiled the plaque at the Wheelhouse, Amber Mill, in Oakerthorpe.
Cllr Lewer said: “Before Whitworth turned his attention to uniformity of standards, the screws used in fitting machinery had been manufactured upon no recognised principle or system. Finding a remedy for these imprecisions became one of the major purposes in Whitworth’s life. His invention of a uniform system of screw threads made mass production possible.”