An isolating decoupler comprising a shaft, a pulley journalled to the shaft, a torsion spring, the torsion spring comprising a flat surface planar in a plane normal to the rotation axis A-A on each end of the torsion spring, a one-way clutch engaged between the torsion spring and the shaft, a weld bead joining a torsion spring end to the one-way clutch, and a weld bead joining the other torsion spring end to the pulley.