What does it mean to set a dial bore gage? Setting a dial bore gage refers to the process of aligning the gage to a required zero point. The zero point is the nominal size, or reference point, that you use when taking the measurement of a bore. There are a number of ways to set a dial bore gage, but the end goal is always to match the zero readout of the gage to the nominal size you are striving for. The outcome of a properly set dial bore gage is being able to easily read off the measurement of a bore as it compares to the zero point on your gage. Any variation away from the zero point is your final measurement. Setting your dial bore gage before each use is important to ensure accuracy in every measurement.