A Kailua High School shop teacher and robotics coach accused of injuring a student with a hammer pleaded no contest this morning to third-degree assault.

David Izumi, 51, said he didn’t intend to hurt the student. He said he was swinging the hammer down in frustration when he saw it was heading for some glass. So he tried to stop his swing when the hammer slipped out of his hand. He said he immediately apologized to the student and told him he loved him.

Izumi is asking for a deferral of his no contest plea to give him the opportunity to keep his criminal record clear. He is also fighting his termination as a teacher.

The judge and the prosecutor want a presentence investigation before deciding whether or not to go along with Izumi’s request.

Kaneohe District Judge David W. Lo set sentencing for next month.