A one-piece cup-shaped metal poly-V pulley has an annular flange formed with a series of relatively narrow, deep, V-shaped grooves which have thickened groove valley walls adjacent the open end of the flange, and the annular flange terminates in an outturned radial stiffening flange. The series of poly-V pulley grooves is adapted to engage a Poly-V Belt in a Serpentine drive or conventional Poly-V drive train.
The poly-V pulley is made by forming a cup-shaped blank with a generally cylindrical annular flange which terminates at its open end in an outturned radial flange. A series of wide opening, shallow, corrugation-like V-shaped grooves then is cold rolled in the cylindrical flange by outwardly and inwardly displacing portions of the flange wall to form rounded groove valleys with intervening rounded crests, and slightly thinning the flange wall metal in the crests and valleys while presenting appreciable groove side wall thinning. The groove walls then are axially squeezed to compress the walls to sinuous shape while maintaining constant the radial dimensions of the inner and outer rounded surfaces of the grooves during axial squeezing. The sinuous formed flange wall then is roller worked, compressed and extruded to form sharp V-shaped outer groove crests and thickened metal in the groove valley walls.