Abstract: An adjustable clutched handle for turning the drive shaft of a tuning peg assembly on a stringed instrument, such as a guitar, and a linear extension tightening post. The clutched handle includes a tubular handle element having a transverse hole formed perpendicular to the axis of the handle element. A generally tubular adapted sleeve, keyed to the end of the drive-shaft, includes a pair of flat drive surfaces on its outer surface. A pair of pistons, sized for movement along the axial bore, are biased against the drive surfaces by a pair of springs. The springs are held in place against the pistons by an adjustable cap. When a predetermined tension has been reached, the force of the springs holding the piston against the drive surfaces is overcome to allow the handle to free-wheel about the drive shaft. The provision of a linear extension tightening post reduces the tendency for the instrument to become out of tune.