By 1801 Houldsworth was running the spinning business at Woodside as a separate concern, Henry Houldsworth and Co
Later he moved the business to Cheapside Street, Anderston.
His son, John Houldsworth (1807-1859), entered the family business and rose to become head of spinning. John and his other son, William Houldsworth, became partners in the business which became Henry Houldsworth and Sons.
Recognising an opportunity in the new iron trade, they started the Anderston Foundry and Machine Works also in Cheapside Street, for the purpose of making and repairing machinery for their mill.
The foundry business continued even as cotton spinning declined.