Abstract: A cutting tool holder has a holder body and a vibration damping weight assembly. The holder body has opposing first and second side surfaces and a top surface extending therebetween, and an insert mounting portion located at a front end of the holder body adjacent to the top surface. A weight aperture opens out to the first and second side surfaces and has an aperture inner surface. The weight assembly is located within the weight aperture, having a first and second weight portions, a damping ring located along the aperture inner surface, and an actuating member interfacing and urging the first and second weight portions away from one another, such that each weight portion presses against the damping ring within the weight aperture.