Jacob Glenn, who lives care of an address in Alexandra Road, admitted possession of amphetamine and the weapon in a private place in March.
He was appearing at Boston Magistrates’ Court for sentence following an adjournment at the request of the Crown Prosecution Service.
Magistrates were told officers went to the address on March 14. Glenn was arrested and the amphetamines were found as well as the knuckleduster.
The court was told Glenn was currently on post sentence supervision following his release from a 28-week prison sentence for assault.
Mitigating, Helen Coney said it was an offence to possess an offensive weapon even in private, but Glenn had not been aware of this and had bought it for protection following being assaulted by someone who had gone into his room.
She said he seemed to be doing 'reasonably well' on his post sentence supervision.
The magistrates fined him £80 in total and ordered him to pay a total of £119 in court costs and charges. They also ordered the destruction of the amphetamine drugs and the weapon.
Also at Boston Magistrates’ Court, a Skegness man admitted stealing cosmetics in order to buy alcohol so he could continue to drink.
The court heard Desmond Scott, 58, of Prince Alfred Avenue, had spent all his money on alcohol the previous evening.
Prosecuting, Marie Stace told magistrates Scott went into Boots in Lumley Road at 8.30am on February 20, took £121 worth of cosmetics and left the store without paying, being identified on cctv later.
She said he had last been convicted for four charges of shop theft in September 2019.
Mitigating, Mark Hudson said Scott had quarrelled with his partner and had started drinking the previous evening and simply wanted to continue to drink but had no money left so had stolen the cosmetics.
The magistrates advised Scott that he should go to an alcohol advisory organisation, ordered him to pay £121 in compensation and court costs of £85.