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Armstrong Whitworth and Co (Tools) Ltd, London and Tynemouth
Armstrong Whitworth and Co (Pneumatic Tools) Ltd
Presumably this was developed from the pneumatic tools activity at Scotswood Works of Sir W. G. Armstrong Whitworth and Co (Engineers)
1954 Supplied tools to car manufacturers (see advert)
1961 Manufacturers of electric and pneumatic tools. 354 employees. 
By 1962 Armstrong Whitworth and Co (Pneumatic Tools) Ltd had changed its name to Thor Tools Ltd.