In 1830, jointly with John Young of Wolverhampton, he took out patent no, 5880, an improved design of latch bolt and lock. The two agreed to divide the patent into rim lock use and mortice lock use, James Carpenter going on to construct rim locks while John Young had the right to make mortice locks. Carpenter named his rim lock "Number 60". It became known as "Carpenters lift up lock". It was his invention to make the latch perpendicular instead of horizontal, which renewed the vitality of the town's staple industry. As his business grew he erected a large factory in New Road, known as Summerford Works. James Carpenter died in 1844, aged 68,