|In 1743, he was trying to repair the handle of a customer's knife when he made a mistake which was to change his future. The knife handle was very decorative, made form silver and copper. During the repair, Thomas had to heat the handle, but he heated it too much and the silver started to melt.
When he examined the damaged handle to see if he could recover it, he noticed that the silver and copper had fused together very strongly. Experiments showed that the two metals behaved as one when he tried to reshape them, even though he could clearly see two different layers.
Boulsover carried out further experiments in which he put a thin sheet of silver on a thick ingot of copper and heated the two together to fuse them. When the composite block was hammered or rolled to make it thinner, the two metals were reduced in thickness at similar rates.
Using this method, Boulsover was able to make sheets of metal which had a thin layer of silver on the top surface and a thick layer of copper underneath. When this new material was used to make buttons, they looked and behaved like silver buttons but were a fraction of the cost.
Strelley Pegge of Beauchief Hall loaned Boulsover the money to start a new business making decorative items from this new material which came to be known as Sheffield Plate. Boulsover set up a partnership with Joseph Wilson to make buttons, buckles, spurs and small boxes out of Sheffield Plate. The business was very successful and the process was soon copied by several other maunufacturers, including Matthew Boulton in Birmingham.
Joseph Wilson eventually left the partnership and set up on his own. Wilson added snuff making to his business. This snuff making business was the basis of the Wilson family's prosperity. The water powered snuff mill was operated in Sharrow, on the River Porter until recently.
Thomas bought Whitely Wood Hall from his friend Strelley Pegge in 1757 and moved his family out to these luxurious premises.
Shortly after this move, Boulsover became involved in the Trust which set up and operated the Sheffield to Leeds Turnpike. The Act of Parliament was granted in 1757 and the road was completed in 1759.
In 1760, he bought land just down the hill from Whiteley Wood Hall, on the River Porter, from the Duke of Norfolk. Thomas built workshops at the side of the river and used water power to roll steel products. The cottages he built for the workers at the rolling mill are still in use. He continued with the button making business at the old Fulwood corn mill further upstream on the River Porter.
Thomas' wife Hannah died in 1772 and was buried in St Paul's Church Sheffield.
Thomas died on Tuesday 9th September 1788 and was buried alongside his wife Hannah.