William Plant
The name William Platt was well-known in the hat-making business, as makers of wooden blocks on which hats and caps were moulded.
There were two block-making companies in Manchester with the name William Plant.
The business of William Platt located at 67a Great Ancoats Street, Manchester closed in 1976, when Walter Plant died at the age of 91. A hat block-making business was established in Stockport in 1828 by Walter's grandfather, William. William Plant and Sons moved to Rochdale Road in Manchester. In 1892 Walter Plant Jr., father of Walter, left the family business and set up as a hat block-maker in Hilton Street, later moving to Great Ancoats Street.
The above information is condensed from here[1]. This source containes a great deal of information about the trade.
After closure in 1976, equipment, blocks and records were taken to what is now the Hat Works Museum, Stockport. See here.
Newspaper Reports
1949 'The Plants
As a footnote to my mention of the retirement of Mr. J. B. Plant, hat-block manufacturer, trading in Sharp - street, Rochdale Road, as William Plant and Sons (this Diary, December 1), it is pointed out to me that other grandsons of the original William Plant are in business as makers of metal and wood blocks in Great Ancoats-street, Manchester, under the title of William Plant. Owing to the similarity of names there have been many inquiries from people who believe that the firm of William Plant, of 67, Great Ancoats-street, is closing down. This is not so. It will carry on the traditions of the founder of the hat-block industry.'[2]