Detecting Forged OS Punctures on Australian Commonwealth Issues

What are OS Punctures?

Stamps punctured OS were used by Federal Government departments - OS standing for On Service. They had been in use in some states prior to Federation, so the idea was not new. It is believed the original purpose of the puncture was to reduce pilfering of postage stamps by government employees for private use.

Commonwealth OS punctures come in two types - Large OS (known as Type G) and Small OS (known as Type H). When the first commonwealth issue of stamps was made in 1913, the Large OS puncture was used. However, it was quickly found that the large hole size combined with the overall size of the two letters so weakened the paper that when stamps were being separated from the sheet, many would be spoiled because the weakness produced by the pattern of holes provided less resistance than the normal straight line of perforations.

The Large OS puncture was quickly replaced with the Small OS puncture, shortly after the release of the KGV Head stamps in July 1914. No KGV stamps were issued with the Large OS puncture.

How Were OS Punctures Produced?

Stamps in the Kangaroo and KGV series were printed in sheets of 120 stamps arranged in left and right panes of 60, with each pane comprising 10 rows and 6 columns. There was a central gutter between the two panes. The steps in the production process are believed to have been:

  1. print the stamps
  2. apply gum to the reverse of the sheets
  3. perforate the sheets (this is the regular perforations, not the OS puncture)
  4. apply an OS puncture to any sheets deemed not good enough for issue to the public
  5. store the sheets until required

When a request was made for a supply of stamps punctured OS, those already punctured were supplied, with further sheets removed from storage and punctured as required. Each sheet was punctured one row at a time, by a device similar to that shown below, comprising 12 separate OS punch heads.

 
Large OS
(Type G)
(issued 1913)
   
 
Small OS
(Type H)
(issued 1914-1930)
 
 
  Between 1927 and 1930, five other stamp issues were also punctured small OS. Two of these (1928 3d Kookaburra and 1930 Sturt) used Type H small OS puncture, while the other three issues (1927 Canberra, 1929 3d Airmail and 1929 WA Centenary) used an old OS puncture known as the Melbourne OS, or Type F, which had previously been used by the Note Printing Branch in Melbourne to puncture various state issues.  
  The Melbourne OS
(Type F)
(1927-1929)
 

 
The photos at left show the final perforating machine used by the Victorian Government Printer to apply VG punctures to stamps, until their discontinuance in 1988. There are no known photos of the Commonwealth OS machine, but it is very likely to have been of a similar style to this one.

If you look carefully, you will see there are only 10 different punch heads, not 12 as on the Commonwealth machine, but the process was the same. A pile of sheets, believed to have been between 5 and 8, was punctured at a time, the sheets being fed between the two horizontal silver bars. Once a row of stamps was punctured, the pile of sheets was advanced so the next row of stamps was aligned with the punches, and the process repeated.