Abstract: A manner of reducing or eliminating chip packing in gear cutting tools, especially in bevel gear cutting tools wherein the back surfaces of at least some cutting blades are modified by the introduction of a rake angled surface and/or a hook angled surface thereby resulting in an opening-up of the gap between successive cutting blades in a direction radially or axially away from the cutting tool. Such an opening-up facilitates the removal of chips from between the cutting blades as the cutting tool rotates during cutting.