I agree with Corneel; its unlikely the mark has any connection with the pitch of the plane. But you have to ask the question as to why someone would go to the cost of having a stamp made up to specifically identify its use from any other trade. Its unlikely that Carpenters, or Joiners, would have shared the same workshop as a Cabinet Maker. Trades within the U.K, no different to Australia, were strongly influenced by their associated union, and generally little allowances were made to work outside your trade description. As a result, certainly throughout the 20th century, most employers enrolled their apprentices into a dual certification of Carpenter & Joiner, as this added much more in versatility to the work that could be undertaken. Bearing in mind that there has traditionally always been a close association between the work undertaken by a Carpenter, and a Joiners role, within the building trade. Much closer in association than that of a Cabinet Maker, who would in most cases have been called upon to complete his service as an independent contractor. As to the likelihood of stamps credentials, its quite possible the owners surname was CABINET. ( possibly French, where the surname is much more in common use, with the T pronounced silent, just like the French wine CABERNET).
Its of interest to note that a double iron was being used at York Pitch as early as 1880. One tends to consider that a double iron was restricted to common pitch only. It does pose an interesting question over what time period the practice of setting the cap iron within a close tolerance of O.5MM was deemed necessary to combat tear out.
