A self-closing hinge has a housing shaft section with a bore extending therethrough in a direction substantially parallel to a longitudinal axis is attachable to a first rotatable member. A bore extends through the housing shaft section. The cross-sectional profile of the bore in a plane orthogonal to the longitudinal axis has at least one arcuate portion and at least one non-arcuate portion. A roll pin rotatably disposed in the bore has substantially the same cross-sectional profile as the bore. A pair of shaft members, each having a shaft-member body attachable to a second rotatable member, has a pin inserted in an interference fit in the opposed ends of the roll-pin bore. The pins have a cross-sectional profile corresponding to the roll-pin cross-sectional profile.