Spirally-twisted steel posts are widely distributed across Australia, but are not particularly common. They date from the late 1920s, and a persistent rural myth is that they were screwed into the ground. There are both right-hand and left-hand spirals, but left-hand posts are much more common. What’s the story behind them?
The post and the patents
The Corkscrew Post is a steel post with a distinctive shallow H-shaped cross-section, spirally twisted into a corkscrew over most of its length.
Three patents cover the post, and more importantly, the machines to make them:
George David Watson (engineer, 14 Mayfair Street, Lower Rickerton, Christchurch NZ) An improved fence standard. Australian patent 25,045/25. 21 September 1925. (IP Australia: 1925025045).
George David Watson (engineer, 14 Mayfair Street, Lower Rickerton, Christchurch NZ) Improvements in bar twisting machinery. Australian patent 25,431/25. 13 October 1925. (IP Australia: 1925025431).
Nine months later, a more efficient machine was patented.
Invented by Septimus Robert Askew and assigned to the Corkscrew Steel Fences Limited (115 Pitt Street, Sydney) Improvements in bar twisting machinery. Australian patent 2,631/26. 2 July 1926. (IP Australia: 1926002631).
The posts were manufactured by the Corkscrew Steel Fences Ltd at Lithgow (NSW) and advertised by The Commonwealth Wool & Produce Co. Ltd (Sydney, NSW) and retailers from early 1926 to the late 1930s. Some were exported to South Africa.
Left-hand and right-hand twists
The initial machine twisted pairs of hot-rolled bars in opposite directions, producing both right-hand and left-hand spiral posts. However there are markedly fewer left-hand posts in fences. This is a consequence of the company changing to Askew’s machine that twisted a single bar at a time.
Killed by better design and aggressive competition
Unfortunately for Watson and the company, the posts bend easily, and worse, they came onto the market at the same time as Waratah’s famous Star Post. With a far stronger design and aggressive marketing, the Star Post quickly dominated the market for steel posts, and the Corkscrew Post faded within a few years.
The myth
A widespread and persistent rural myth is that Corkscrew Posts were screwed into the ground using some form of tool fitted over the top. However no informant has ever produced such a tool, nor had first-hand experience of using one.
Advertisements dispel the myth, with at least one saying that the posts are: “EASILY DRIVEN with 7-lb. hammer … yet quickly withdrawn by unscrewing if required for further use elsewhere.” (The Commonwealth Wool & Produce Co. Ltd 1928a, p. 271). One illustrated ad shows a farmer hammering a post into the ground.
Hammering a Corkscrew Post into the ground (detail from The Commonwealth Wool & Produce Co. Ltd 1928b, p. 65)
Confusion with the military corkscrew post
Another corkscrew post is occasionally seen in farm junk piles and collections, but not in Australian rural fences. And this may be the origin of the myth about the civilian posts.
This is a military post developed for rapid and silent deployment of barbed wire entanglements. It is made of steel rod, usually about ⅝” diameter, with a sharp point at the upper end, three or four pigtail loops in the stem, and a corkscrew at the base. They were first used in World War 1, and have been used in all subsequent wars up to (and probably after) the Falklands War of the 1980s.
References
Newspaper references are from TROVE (https://trove.nla.gov.au/newspaper/result?q=). and individual URLs are not given.
The Commonwealth Wool & Produce Co. Ltd. (1928a) Fencing posts that last! [Advertisement]. The Pastoral Review (16 March 1928), 271.
The Commonwealth Wool & Produce Co. Ltd. (1928b) Corkscrew steel fencing posts [Advertisement]. The Pastoral Review (16 January 1928), 65.