Here is the answer I was looking for some time back. It has been great
revision for me and I have had considerable help from a mathematics forum.

The problem was to find the set-up angles required to make a skewed milling
cut in a rectangular block following given angles on three of its surfaces.

Image he

http://i486.photobucket.com/albums/r...=1281058640The desired angles are A, B and C in planes YOZ, XOZ and XOY respectively.This is a right handed coordinate system with angles X - Y, Y - Z and Z -X being +ve.1. Align vice jaws // X.2. Set block in vice so that line at angle A is // to XOY3. Tilt vice by angle D to XOY. WhereD = atan(cosAtanB)4. Rotate vice by angle E from XOZ. WhereE = atan(cosAsinC/(cosCcosD-sinAsinCsinD))John.