In addition to his brassfoundry trade, he gradually added the manufacture of brass, copper, and tin tubing, gas-fittings and chandeliers, iron and brass bedsteads, ship's fittings, brass fittings for shop fronts, and general architectural ornamental metal work of all kinds. He afterwards purchased the large establishment near his own works, called the Union Rolling Mill, where he carried on a very extensive wholesale trade in rolled metals of every kind, and brass and copper wire of all descriptions; and he was, for forty years, largely engaged in the coal business.
For a very long period Mr. Winfield was the sole proprietor of the extensive business he had created. He was assisted by his only son, Mr. John Fawkener Winfield, whose promising career was cut short by untimely death. This was a blow from which Mr. Winfield never entirely recovered. He soon afterwards took into partnership his relative, Mr. C. Weston, and his old confidential clerk, Mr. J. Atkins. His health began to fail about this time, and he retired from the active control of the concern, retaining, however, his position as head of the firm until his death.
His marvellous success did not arise altogether from brilliant mental qualities. I am disposed to attribute it to higher reasons. It seems to me that his high moral sense of integrity and right, and the benevolence of his character, had more to do with it. These led him constantly through life to give his customers excellence of quality in the goods he made, combined with moderation in price. In the execution of a contract he always gave better rather than inferior goods than he had agreed to supply. He would never permit any deterioration of quality either in material or workmanship. Where his competitors sought to reduce the cost of production, so as to enable them to sell their goods cheaper, his ambition led him to raise and improve quality. The fact of his goods being always honestly made, of good materials well put together, gave him the preference whenever articles of sterling excellence were required. He was one to whom the stigma implied in the term "Brummagem" would not apply, for he consistently carried out principles of integrity in business, and so earned for himself the right to be held up as a type of a high-minded, upright, conscientious English merchant.