Ori alaidun (ọpa alaidun) jẹ awọn ẹya akọkọ ti alaidun ati awọn irinṣẹ ẹrọ milling CNC, fun apẹẹrẹ ipoidojuko ẹrọ alaidun, ẹrọ alaidun petele, ẹrọ alaidun arinrin.
Awọn ori alaidun ti wa ni lilo fun alaidun, Circle ita ti alaidun, oju opin alaidun, iho akaba alaidun, oju opin iho alaidun, ge iho ati iho oruka lode ati sisẹ miiran.
Eto konbo ori alaidun yii ni ori alaidun, Awọn ọpa alaidun, Boring Shank, o jẹ pipe fun ẹrọ milling.