ORIGINAL: KitBuilder

I have done the following in the past and it works real well.

Place your stock between two sizes of Piano wire that will give you the final taper you want.. Tape the wire down to our table witt tape running ealong the length of the wires. Place the small diameter end near the end of the table so you snading block can angle below the table. Then start standing. You can sand all the way down and make the piece the same on both sides by adjusting the leading edge, or flip the piece after a bit and sand the other side as well. Your sanding block will stop sanding the piece once it starts to ride on the piano wire. The tape will wear but not enough to be an issue for as it gets close you can go to finer paper.