A Brooklyn art teacher who allegedly threatened to machine-gun her Bay Ridge high school in a Columbine-style rampage was arraigned yesterday and ordered held on $100,000 bail.

Sabrina Milo, 34, allegedly went off in the teacher break room at Fort Hamilton HS on March 27, saying she’d take a “machine gun under a trench coat and it would be Columbine all over again.”

Thirteen people were slain in the 1999 assault on Columbine HS, outside Littleton, Colo.

Milo made the threat in front of three teachers, a prosecutor said yesterday in Brooklyn Criminal Court. They told the principal, who told the city Department of Education.

Milo was busted Friday and charged yesterday with making terroristic threats, a Class D felony.

Her lawyer, Andrew Stoll, said at the arraignment that she was “not a threat to anybody.”