It is unclear as to when the Iron Hoop Manufacturers’ Association (IHMA) was formed or dissolved. The association represented manufacturers of iron hoops which were an important part in keeping the stays of wooden barrels together. Large numbers of wooden barrels were made for the herring industry as well as for other food and drink industries. The association had been formed by various manufacturers to agree a common price between all manufacturers for hoops produced for national and international sale. It had been noticed as early as 1917-1919 that sales of iron hoops were decreasing due to several factors amongst which was the iron was being replaced by steel, which had its own association. It was suggested, as a result of declining sales of both iron and steel hoops, that both associations should merge, in order to be able to discuss the common price of hoops made by companies who were members of either of the two associations. Having one association made the discussing of mutual interest easier to deal with as well as promptly. It is not known whether the two associations did in fact merge to become one association.

Henry Knowles was a business man with a company based in Brazenose Street, Manchester. He had previously worked in Warrington for Monks Hall and in Sheffield, possibly for Fox's the umbrella manufacturer. In Manchester, Knowles acted as Secretary for several organisations connected with the iron and steel industry. He is known to have travelled on business and to attend industry meetings across Europe during the 1930s.