How to re-align tailstock?

[Toolguy]

The button method. This is one of the easiest ways to do it. Once the buttons are made, put the small end of one in a collet or 4 jaw chuck, make sure it's running true. Put the other one on a center in the tailstock and bring the 2 big ends together. Measure across them horizontally with a mike as you adjust the tailstock side to side. When the reading across both buttons is the nominal diameter of the button, the tailstock is centered.