Abstract: The tuning mechanism comprises a support which carries a shaft on which is mounted an arm that extends generally as a radius of the shaft. The arm has a turnable assembly that receives and retains a string of the instrument, and the assembly may be turned to tension the string. Further, the arm is rockable relative to the support for further adjusting the string so as to afford fine tuning. The turnable assembly is received in a bore in the arm and is made up of a stud over which is sleeved a coil spring via a frictional fit and the spring is connected at one end to the arm whereby the stud, to which the string is attached, is limited to one-way turning in the direction of string tightening.