In a shocking victim impact statement read out at Sheffield Crown Court, the terrified pensioner described how one of the masked men sliced his hand with a machete that cut 'like a knife through butter,' and only stopped when it hit bone.
The man, now aged 71, was struck with the machete when he put his hand up in an attempt to defend himself.
He said: "If I hadn't have put my hand up it would have hit my neck, and probably killed me."
The man was left with nerve damage in his hand following the attack, the court heard.
Defendant, Jordan Simpson, of New Cross Drive, Woodhouse, was one of a group of four males who orchestrated the raid on the pensioner's home on November 21 last year, after hearing of the cannabis operation he was cultivating on the first floor of his property.
A neighbour told the police how the four men arrived at the property in a car and heard one of them shout: 'Get upstairs and get them drugs,' before the group kicked down the front door to gain access.
Simpson, aged 25, is believed to have stayed outside with the car while the other three stormed into their victim's home.
Despite being attacked with the machete, the elderly man attempted to stand up to the three masked men and they eventually backed off before leaving the premises, the court heard.
"The police were deployed and arrived in time to see the car with a number of males, including the defendant, and gave chase," said David Wain, prosecuting.
Simpson was arrested by police a short time later, by which time he had helped to dispose of one of the machetes in a bid to conceal evidence.
He was found to have traces of the complainant's blood on his jeans, the court heard.
After initially telling police that he only got into the car after the robbery took place, Simpson, who has a lengthy criminal record, eventually pleaded guilty to offences of robbery and possession of an offensive weapon.
The other three men involved in the raid have never been identified, the court heard.
Defending, Vanessa Saxton, told the court that Simpson had been bullied by others to allow them to use his property for selling drugs and other criminal activity, a practice known as 'cuckooing'.
"That's what happened to this young man, and unfortunately, despite his size and appearance, his demeanour is very much that of a gentle giant," said Ms Saxton, adding: "He was told to put on a balaclava and kick in the door, and he followed these instructions. He knew they had weapons and intended to steal a cannabis operation. He knew these weapons were to be used to remove those items. He knew the danger of these people, and if anyone was inside he knew violence would be used towards anyone if they put up any resistance."
Judge Sarah Wright told Simpson tshe accepted he was not one of the three men who burst into the property,and jailed him for eight years for his part in the robbery.
She said: "This was a serious, violent and shocking offences with far reaching consequences."
*South Yorkshire Police have been asked to provide a custody image of Simpson.