Lee Hickling, 46, admitted losing his temper with the woman, who lived at his home rent free, after she and a friend returned to his house drunk and began playing loud music.
Lincoln Crown Court heard Hickling went in to the woman’s room and remonstrated with her to turn the music down.
When the request failed Hickling, who had also been drinking, went to his kitchen and armed himself with two knives.
Gordon Aspden, prosecuting, told the court: “Rather foolishly he went back in to the room.”
“During a fracas in which they tried to disarm Hickling, his lodger suffered a superficial cut to her left forearm.”
“It was described variously as between 2cms and 4cms in length and around an inch square.”
Hickling, who had no previous convictions, called the police himself once the incident had concluded.
In mitigation, the court heard Hickling was being treated with anti-depressants and had not drunk any alcohol for eight weeks.
Hickling, of Devon Street, Lincoln, admitted a charge of assault causing actual bodily harm on 20th November, last year.
He was sentenced to four months imprisonment suspended for 12 months.
Passing sentence Recorder Gareth Evans QC told Hickling: “Out of kindness you allowed these people to stay in your home.”
“They repaid you by coming home legless and playing loud music.”
“When you asked them to stop they ignored you.”
“So far the sympathy is with you.”
“There came a time when you armed yourself with two kitchen knives.”
“The problem with arming yourself with knives is that people get injured.”
“I am satisfied you did not intend to stab her, your aim was to calm them down.”