A vee-board is very useful for fine fret saw work, such as for rough cutting the f-holes, I also find it quite useful for work where the edge of plate (belly or back) needs to overhang, such as using a purfling marker or cutter, or filing edges to shape.

Roger Hargrave outlines how he uses a vee-board in his article Purfling & Edgework in Cremonese Instruments in the library section of his website.

My Vee-Board

Roger Hargrave’s Vee-Board