Firth-Derihon Stampings Ltd. of Sheffield.
Owned by Thomas Firth and John Brown
1919 Private company.
1937 Drop forgers and stampers. "B N C", "B N D" Alloy Steels. "F.D.V.I." Alloy Steels. 
1959 Increased capacity at Darley Dale Works. Large consumer of special steels produced by Thomas Firth and John Brown..
1961 Manufacturers of drop forgings, stampings and pressings in high stress, heat resisting alloys for aircraft and automobile industry and nuclear power stations. 650 employees. 
Sources of Information
- 1937 The Aeroplane Directory of the Aviation and Allied Industries
- The Times,29 January 1960
- 1961 Dun and Bradstreet KBE