Police and navy personnel were on patrol to prevent violence yesterday, which was wai khru day (paying respect to teacher) at Chamni Technology School.
The patrol arrived at Wat Pichai Songkram, in the market, and spotted the group of students acting suspiciously.
The security team asked to search them and found most of them carried knives, a pen gun or giant crackers to be used against rival students.
The police seized a total of 54 knives, one axe, three pen guns and 20 giant crackers.
The students were taken in for questioning at Samut Prakan police station, where they said the weapons were for self-defence. They were to be charged with an illegal gathering of more than 10 people with weapons and having the intention to cause violence.