So I got my mini lathe and will say for a guy that has no idea what he is doing I am impressed. So after a few hours of tinkering with the 4 jaw I feel comfortable indicating work in. I made a spider for the machine from a piece of thick wall 5 inch od with 8 , 1/2-13 cap screws spaced around equaly in two spots around 2.250 between centers of holes. I have a gauge pin set that I am using to indicate with and am having issues. I am trying to set back the shoulder of a smith and Wesson 1917 barrel I cannot get it to run true. The indicator closet to the tailstock I can adjust the screws until its zero all the way around. The go back to head stock and its out there. I adjust until its zero go back to original point its out again too. How do you do this?