Two off duty police officers stepped in when Jamie Claridge swung a 10 inch dumbbell bar at a man who he said had damaged his front door.
Claridge, 32, came up behind Kerry Reynolds in Watford High Street on a Friday evening just before Christmas.
He swung the bar at Mr Reynolds, but the officers intervened before there was any contact, St Albans crown court heard today (Friday).
Claridge, of Wilmington Close, Watford, was convicted of having an offensive weapon on December 20 last year. He had previous convictions for an offensive weapon and possessing a bladed article. He told the jury he had only intended to frighten Mr Reynolds.
David Baird, defending, said Claridge, who came to court in a wheelchair, had broken his leg. He said his partner had lost their child after being involved in a car accident. He said Claridge had never been to prison before.
Jailing him for six months, Judge Andrew Bright QC said: "You have previous convictions for having an offensive weapon and a bladed article. You are ready to get a weapon when it suits you.
"You believed Kerry Reynolds had damaged your front door. There is no justification for arming yourself and setting off with a bar with the intention of using it."
The judge said he reduced the sentence he would have passed from nine months because of Claridge's injury and the loss of his partner's child.