[steamer]

A master machinist showed me this one. Just put centres in both headstock and tail stock. Bring tail stock up to headstock. If the tail stock is centered you should be able to hold a razor blade between the two points. If not, then just adjust the tail stock till it does, and your done. Now if your lathe bed is warped then that's a different fix. You'll need a precision level and shims to make it true over the entire length. Then go back to step one. Hope this helps.