Abstract: A method and apparatus for making small ball size ratio air balls for use with fine pitch bonding tools includes programming an automatic wire bonder to make a predetermined diameter ball on a fine wire. The predetermined ball size, the diameter of the wire to be used is entered as input data in the wire bonder which makes a calculation of the time required to melt the volume of a fine wire tail necessary to create a spherical ball of predetermined size. The free end of the wire tail to be melted is positioned above an aperture in an EFO electrode wand. A predetermined current is applied across the gap between the aperture in the EFO wand to generate a ball on the end of the wire tail. If the ball size deviates from the preselected ball size, the ball may be increased or decreased by an incremental percentage to effect even greater ball size accuracy. Further, the spring force in the wire loop may be adjusted and/or controlled while maintaining the preselected ball size.