Alec Meikle was 17 when he hanged himself at his aunt's house in October 2008 after working as apprentice engineer at Downer EDI at Bathurst.

There he was set alight, feared being raped and had a chart of his mistakes publicly displayed in his workplace, the inquest has heard.

Alec's father Richard Meikle told Glebe Coroners Court on Tuesday, until his deterioration, his son had been a focused, mature young man.

He said Alec had always had good self-esteem and was "exactly the opposite" of depressed before his time at Downer EDI.

As the bullying continued, some of Alec's colleagues became concerned about the level of harassment.

But several had threatened to make Alec's life "a living hell" if he went to management, Mr Meikle told the inquest.

After leaving Downer EDI, Mr Meikle said his son's condition continued to deteriorate to the point where he would panic about leaving the house.

"He was very hard to get out of his room," he said.

"We got him into town to buy a Subway, that was a big trip."

Mr Meikle had told the inquest his son was called "a useless f---ing c---" every day by his supervisor and other tradesmen.

But he rejected defence lawyer Ross Hudson's suggestion some of the colourful language simply came with the territory of a "hardened industry".

"It was used as a weapon. There's a huge difference," he said.

Mr Meikle also said the so-called "Sphincter Dilation Chart" was not a harmless workplace joke and had a major effect on Alec's mental state as he notched up mistakes.

Alec had been occasionally bullied in his early secondary school years, and was called a "sheep f---er" because of his New Zealand accent, he added.

But he stressed Alec had also enjoyed school, in particular the camaraderie of weekend rugby trips, and denied he was "sensitised" to bullying.

The inquest before deputy state coroner Paul MacMahon continues.

* Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14 or the Kids Helpline 1800 55 1800.