A method of mounting rotary scale member on machine part includes: locating rotary scale member on machine part such that scale axis and axis of rotation are substantially parallel, and subsequently arranging at least a first radial adjustment device to contact both machine part and rotary scale member, and manipulating the at least first radial adjustment device to radially displace body of rotary scale member. At least the majority of any radial reaction force, generated as a result of the interaction of at least one of the flexures with a radial stop member against which it is radially pressed, and which is imparted on the at least first radial adjustment device by rotary scale member in opposition to the radial displacement of the rotary scale member, is directed into, and reacted by, the machine part via the contact between the at least first radial adjustment device and the machine part.