ddickey,
You have to take a brass mallet and gently bump the test bar out on the end to get it running true. Leave your jaws tightly snugged, not tight, for this operation. Once trued up, walk around and tighten the jaws and adjust as needed. You shouldn't neeed to tighten the jaws too much on the test bar. It's not like your going to do any cutting on the bar. Ken