In 1910 John Rubery resigned from the partnership and Alfred Owen expanded the product range, that at the time included:

In 1912 there were five departments:

A Metal Storage Equipment department opened in 1932 and Alfred and his brother Ernest William Beech Owen became joint managing directors in 1934.

Expansion continued with the opening of the Armour Plate department in 1937, the purchase of Easiclene Porcelain-Enamel (1938) Ltd. in 1938, the formation of the Airframe department in 1939 and the purchase of a hydraulics company in Warrington, that became known as Rubery Owen Conveyancer Ltd.

During World War II the company turned out all kinds of products to assist in the war effort such as wing flaps, ailerons and tail units for the Lancaster bomber and by 1946 the organisation employed around 16,000 people.

The Metal Aircraft department became the Metal Assemblies department and the Armour Plate department became the Agricultural Plough Division, producing ploughs and components for the Ferguson tractor. Agricultural products included manure spreaders, grain drills, tractor wheels and axles, and components for horse-drawn vehicles.

Other products included pressings, fabrications, general aircraft components, precision assemblies for aircraft, gas cylinders, nuts, bolts, studs, and motor vehicle components such as chassis, axles, wheels, fuel tanks, and discs.

Steel structures were designed and made for all types of single and multi-storey buildings and erected by Rubery Owen in conjunction with the customer's architect or civil engineer.

The company' Structural department was responsible for a number of well-known buildings such as the London Passenger Transport Offices at Westminster (the tallest building in London at the time); the Palace Court Hotel, Bournemouth; Rootes Securities building; Speke aircraft factory; and the Castle Bromwich aircraft works. Local structures include the steel frame for Wolverhampton's Civic Hall, the old South Bank Stand at Molineux football ground, and Birmingham Tramways and Omnibus Department's bus garage. The company also produced pre-fabricated houses for local authorities.

Rubery Owen thrived and took over many other businesses to become one of the major employers in the area. In 1956 the Darlaston factory was re-structured into 7 divisions, each responsible for the design and sales of their products. The divisions were:

Motor Division, Structural Division, Contracts Division, Bolt and Nut Division, Metal Assemblies Division, Metal Equipment Division, and Rowen-Arc Division.

A Rubery Owen house.

A Rubery Owen house showing the light steel frame.

The Darlaston works came under the control of a new company, Rubery Owen (Darlaston) Limited with directors David and John Owen in charge. In 1969 Sir Alfred Owen suffered a serious heart attack and the general management of the group was taken over by the two brothers.

Unfortunately things started to go wrong during the recession in the late 1970s. In June 1979 the company shed 400 employees at the Darlaston factory, and 950 more in 1981. Sadly the Darlaston factory closed in the same year.

The company still has a small presence in the town in the form of Rubery Owen Holdings Ltd., in Booth Street and Rotech Laboratories at Moxley Industrial Centre, Wednesbury.