But instead of stepping on the bus heading to school, he climbed on one going in the opposite direction, marking the beginning of a 50-year tenure in the machining trade.
Yesterday, that milestone was marked at Bison Group, the Dunedin-based manufacturing business founded by brothers Greg and Mark Fahey which has developed a strong international niche in the container weighing and lifting market.
Mr O’Mahony was the first person employed by the brothers and, having been there for 12 years, it was the longest he had worked anywhere, he said.
He was 16 when he left school, a move which disappointed his mother. Black+Decker had just opened a new factory in his Irish hometown and was looking for an apprentice.
While the position was for an electrical apprentice, it was decided after he sat aptitude tests that he was more suited for the mechanical trade and he was offered a tool-making apprenticeship.
He had no idea what that was but his mother said he could leave school if he got an apprenticeship so he jumped at the chance.
After completing the apprenticeship, Mr O’Mahony was keen to have a look around.
He had always wanted to go to Australia, and with family in Melbourne he thought to head there.
But then a workmate started singing the praises of New Zealand so he started looking into that. A job agent in Auckland got him a position at Allflex in Palmerston North.
He was immediately captivated by New Zealand, although he did not think at that stage he would stay here for the rest of his life.
He was also impressed by Allflex, which was then a “classic Kiwi can-do place” which had started from “utterly nothing”.
It had a young workforce and he was quickly integrated as a New Zealander. His then girlfriend — now wife — Annette also turned up from Ireland.
He did work in Melbourne for a while, returning to Ireland when his father died, where a company offered him a job for a year.
The couple thought that was a great opportunity for their two children to experience Irish life and the job turned into six years.
The family later returned to Palmerston North. Mr O’Mahony also had stints working in Tauranga and New Plymouth.
In 1999 they shifted south when he got a job at Fisher & Paykel in Mosgiel. That lasted until the plant closed and manufacturing was moved offshore in 2008-09.
Mr O’Mahony then made his only career change when he spent 18 months with New Zealand Post delivering mail.
It was the only time in his career that he worked without a toolbox, and he enjoyed the change.
He was later approached by Mark Fahey who was looking for someone to help him and his brother with a project.
Meeting the brothers, he was offered an “as and when required” job and spent several years building prototypes and trying to get things to work.
It was the first time he had been involved in a business from the start and he enjoyed working for Bison, which now operated from a factory in Kaikorai Valley.
Bison was recently named fastest growing manufacturing business in the Deloitte Fast 50 regional awards for Otago and the lower South Island.
He now worked four days a week, six hours a day.
“As long as I’m busy, I’m happy. I’ve always been happy making stuff rather than telling people what to do,” he said.
Mr O’Mahony intended on retiring at Christmas and after spending summer in the garden, he would “see what happens”.
