Yes there is error build up, also you need to take into account the amount of pressure (or feel) of the person doing the measuring. That is why we had one or two techs do the calibration or the final measurement. If you need to measure to something closer to +/- .001" you need ...
This is inductance meter I built using 74HC14 IC. Initially I used a DMM as the display device, but on a whim I tried hooking up a moving-coil meter. To my surprise, it actually worked just fine, 1K in series was sufficient to allow a useful calibration and didn't overload the dri...