Forget about that center ! Turn that barstock into a center . Mount your piece between the center you turned in your headstock and your live or dead center in your tailstock . You will be running true to your centers for turning . I do not recommend using a dead center at all ( in a lathe ) as this creates heat , and heat creates movement and expansion . Cylindrical grinding being an exception , dead centers are , well , dead . When you are done with the job , put your barstock next to your lathe . Next job , chuck it up in your lathe and reskim it thus being true once again . OR , buy a adjustable chuck which is quite expensive .