Glad you are still around. I felt pretty embarrassed when I noticed that I responded to thread was several years cold.
The side forces are not really that easy to calculate. It depends. Geometry of cutter, size of cutter, speed of spindle, depth of cut, feed rate of the spindle, sharpness of cutter, amount of lubrication, grade of AL. Most times it is the skill of the operator to adjust on the fly. Computers still can't adjust to circumstances as well as a human operator.