In 1939 the London Acton main works of D Napier & Son needed to expand as part of the war effort and they acquired two new premises at Park Royal.
A test house was built at Coronation Road for prolonged testing of the Sabre engine since it was more out of town and could be better tolerated than in the middle of Acton Vale on Acton High Street.
Across the railway line and A40 was Mansfield Road where the Compnay built a precision investment foundry.
PR1 - Coronation Road, Park Royal
Development Test Houses
PR2 - Mansfield Road, Park Royal
Blade shop, Napiercast precision investment foundry & apprentice school