I TAKE THE BATTERIES OUT of my calipers until I need to have exact dimensions. I use the calipers to measure the exact joints where the hardware intersects the barrels. It's the best way I've found to get an exact fit.
I usually have four calipers that are labeled, clip, centerband, nib and finial. They are set at the beginning of a run for "Batch turning" (i.e. Jr Gent), then reset for each new style.'ve been doing it this way so long the numbers on the digital calipers have become meaningless to me. Instead of using the "stock" digital number for a set, I measure the exact piece I'm turning. I do this because of TOO MUCH variance between the "listed" size and the actual size.
Respectfully submitted.