Abstract: A mechanical emulsifying apparatus makes oil/water emulsions without chemicals and without moving parts. Oil is pumped at a nominal pressure axially into an emulsifying stack of alternately clockwise and anticlockwise abrupt-reversal helical spin-reversing helix disks, with integrally machined separator necks. The stack transfers partially emulsified oil/water mix from one helical disk to the next. Water is introduced directly into the emulsifying stack (for heavy oil, from the side) at a pressure higher than the oil pressure, to shear into the oil stream. The oil/water stream, as it penetrates the oil stream, follows a spin-reversing flow path through the stack. Each disk is cut with a helical pathway, alternately clockwise or anticlockwise, and with a separator neck, for an abrupt transition at a nominal 135 degree angle. The oil and water streams, partially merged, strike the transition at the separator neck between helix disks. This reverses the helical flow abruptly.