Christopher Bradbury, aged 41, made the threat to a member of staff at Aston Barclay car auctioneers in Prees Heath, Whitchurch, after he went to pick up his vehicle on April 13 this year.
Telford Magistrates Court heard that Bradbury "lost his cool" when he found his possessions inside the van had been seized by police.
Bradbury told the worker "I will smash your ******* face in", adding that he had a sledgehammer in his van, and if he did not get his possessions back in 15 minutes, he would "smash all of these vehicles" at the auctioneers.
The colleague went inside the building and one of his co-workers called the police. Bradbury was arrested.
When interviewed by police, he confessed to making the threats, and said he wanted the victim to "feel intimidated" so he would do as he wanted.
Bradbury, of Campbell Road, Stoke-on-Trent, Staffordshire, pleaded guilty to using threatening behaviour and threatening to damage property.
Representing himself in court, Bradbury told magistrates he had been "under pressure" after building his business for the last 12 months, and the tools and documents seized from the van meant he could not do his job.
"I still haven't had it back," he said, relating to the items seized. "I would like to apologise for losing my cool."
Head magistrate Sarah Richards told Bradbury: "You know you were wrong to use that type of language and threatening behaviour. You cannot intimidate people in that way."
Bradbury was handed a 12-month conditional discharge, meaning if he commits any other offences in the next year he can be re-sentenced for the threats. He must also pay £135 in prosecution costs and a £26 victim surcharge.