Convicted forger William Henshall was chosen to cut and counterstamp these coins. Henshall worked as a metal plater and cutler in England. On an 1811 New South Wales muster list he was listed simply as a 'convict', without reference to his trade. It is believed Macquarie probably learnt about Henshall's metal-working skills by reputation.

In researching the history of Henshall and the holey dollars, numismatic experts Peter Lane and Peter Fleig found that Henshall arrived in the colony of New South Wales after being sentenced in 1805 to seven years transportation for his involvement in counterfeiting.

He provided authorities with information about other forgers and ways of combatting the crime in exchange for an assurance his wife and family would accompany him to New South Wales. Henshall arrived in the colony and was granted an absolute pardon on 12 September 1812, six months before his sentence was due to end.

Macquarie provided Henshall with a workshop in the basement of a building known as 'The Factory' to make the holey dollars and dumps.

This building, used by government printer George Howe, was near the corner of Bridge and Loftus streets, by the eastern bank of the Tank Stream. It was effectively Australia's first mint, with Henshall Australia's first mint master.

Macquarie initially anticipated that the task of converting the 40,000 Spanish coins would take three months, but the project took over a year to complete. Henshall had to experiment with making the necessary machinery, which proved difficult. It seems that a drop hammer, as opposed to a screw press, was used to stamp the coins.

Henshall stamped the coins with their new value and 'NEW SOUTH WALES 1813'. He incorporated his 'H' initial into the spray of leaves of the counterstamp design and also inscribed his initial between the words 'FIFTEEN' and 'PENCE' on the dump reverse dies.

The first batch of new coins was delivered to Deputy Commissioner-General David Allen on 25 February 1814. The final batch was delivered in August of the same year.

Henshall left the colony for England in 1817. It is not known what became of him.