If you have this saw,

http://www.harborfreight.com/cpi/cta...emnumber=42307

building an adjustable (length) arrow rack is not impossible but will not be a simple task. Using a "chop" saw to cut shafts will a bit more cumbersome and time consuming. In addition, the saw arm and blade must be perfectly stable…no side movement.

Also important is to make sure that blade is absolutely sharp so that the blade will cut the shaft without having to apply much down pressure. Otherwise, you could crimp the end being cut.

You may end up putting time and money into building an accurate and stable rack to mount with the saw, and end up with something that is to much trouble to use and does not properly cut your shafts.