After you purchase a coaxial indicator, you will want to test it before using it for an official measurement. It is important to check that the tool is functioning properly. First, you will set the coaxial indicator up in the holding tool and attach one of the probes. You want the probe to be positioned as close to the center of the bore you are measuring as possible. Second, turn on the holding tool so that the coaxial indicator is spinning. While it is in motion, you will assess both whether the coaxial indicator is touching the edges of the bore and whether it is properly centered in the middle. At this step, if there is any movement on the dial it is an indication that the tool is not over the center of the bore. Third, while it is still running, adjust the zero point roughly so that it is more centered. Fourth, stop the coaxial indicator from spinning and adjust the probe to align with the x- and y-axis. Fifth, let the coaxial indicator spin again to see whether the dial is moving and whether it is now properly centered. You may need to repeat these series of steps before it is in the middle. Once you have practice, this process it comes faster and simpler. If necessary, you can take the coaxial indicator apart to test the internal bearings and make any needed adjustments.