A quick-release knife connector for use on a rotary disc cutterhead having an asymmetrically shaped knife nut with a first portion providing a bearing surface for an aperture in the knife and a second portion which inhibits axial movement of the knife from contact with the first portion. A capture spring having an aperture for partially receiving the second portion prevents accidental release of the knife. The asymmetric orientation of the second portion and placement of the aperture on the capture spring assures that the knife nut is properly oriented when installed.