There is a general rule that some follow to make sure their carbons are as straight as possible. Moast times if shafts are out of whack it is at the ends--either or both. So when you cut your shafts down take an equal amount from both ends. This usually works quite well. True, you'll still get one out of tolerance once in a while, but I've had a few aluminums and even an accosional ACC that just doesn't want to shoot with the group. That's where the arrow cutoff saw comes into play and make some 6" arrows for the trashcan.