Turned down the new backing plate to fit this 5 inch Chuck and brought it back to less than 2 thousandth run out on the dial indicator. I was very nervous to try this (absolute amateur) but it came out well. The tightening sequence of the backing plate bolts was the key, set up a dial indicator on a nice round part like a drill bit shank, turn the chuck to find the high spot tighten the variance out, repeat. My old chuck was 90 thousandths plus out, so happy with the new one.