You cannot check backlash over a distance like 1" or more, if you try you'll start measuring pitch error in the leadscrew which is a whole different animal. To check backlash you run the axis a good distance (say 0.1") one direction to take out any backlash and preload your indicator. Then move in 0.001" steps the opposite direction. As soon as the needle move on the indicator - STOP - . The difference between the number of steps you made, lets say 5 - 0.001" steps, and how far the indicator moved, let's say 0.0005" is the backlash. You should repeat the measurement several times and be able to get the same result. If you can't get a reputable result then you have other mechanical issues that need to be resolved (something loose, flexing, etc.)