Ian Masterton suffered repeated violence and a string of chilling threats after the group burst into his home when he was alone.
Mr Masterton, who was 54 at the time, eventually revealed where the cash was in his home after being threatened with escalating violence.
He told a court: “I didn’t know what they were capable of doing or how far they would go. I wanted them out of my house.”
After the gang, armed with axes, forced their way into his home in Lochore, Fife, he was trussed with cable ties and battered.
He was dragged about his ransacked home as the gang sought his savings.
During the ordeal a threat was made to put his head in a wood-burning stove where the cinders were still red. He said he was also threatened with an axe and boiling water.
Mr Masterton, who had a garage business, said: “While I was on my knees, the boy came to me and put a dish towel over my head trying to suffocate me. The other one… he was going to boil the kettle and put the water over my head.”
A threat was also made that if the gang did not get money they would be back for his son.
At one stage he managed to break cable ties binding him and thought about jumping from a window, but realised it was double glazed. His attempt to escape was thwarted and he was trussed up again.
After the intruders got the cash they left and Mr Masterton managed to raise the alarm, which led to a major police investigation.
He agreed that he had lost “quite a substantial amount of money” and said he had not received any of it back.
Mr Masterton was forced to relive the ordeal in the witness box at a trial at the High Court in Edinburgh yesterday before four of his attackers entered guilty pleas that were accepted.
Gary Carcary, 20, of Caol Court, East Kilbride, Lanarkshire; Mark Dickie, 28, of Woodlands Crescent, Johnstone, Renfrewshire; John McLeese, 28, of Witches Linn, Ardrossan, Ayrshire; and Andrew Dickinson, 28, of Glencoats Drive, Paisley, Renfrewshire, admitted assaulting and robbing the victim of around £90,000.
Police later learnt that Carcary had sent a picture to a woman friend of a wad of cash. When his white Audi A4 courtesy car was searched they found a homemade balaclava, cut-up stockings, gloves, a hooded top, phone and a receipt for two Rolex watches bought for more than £11,000.
The judge, John Morris QC, deferred sentence on the four robbers until next month.
All four were remanded in custody.