Specialist Aviation Manufacturing (formerly Bowman & Sanderson) was formed in 1955. The company offers sub-contract machining of components placing particular emphasis on Quality, Capability, Experience, Reliability and On-Time Delivery.

Hermitage Sheet Metal was founded in 1965 on the principle of always producing work to an excellent st​​andard. The company has grown significantly since then, but this philosophy is still at the heart.

In January 2014 both companies joined the SA Group of companies and, whilst continuing to trade separately under their individual identities, together they provide an industry-leading manufacturing practice through innovative initiatives intended to increase quality and performance for all customers.

2015 saw the formal merger of the Hermitage Sheet Metal and Specialist Aviation Manufacturing creating a new precision component engineering business, HSM Aero. Both companies are extremely proud of the quality of their staff, the quality of their work products and the quality of their service. Customers can expect to see increased efficiencies, faster turnarounds and the continued high quality work already seen from Hermitage Sheet Metal and Specialist Aviation Manufacturing.