The many design modifications available in snap gages enables them to measure some of the most difficult dimensions, right at the point of manufacture.
All fixtures for part gaging will have some amount of deflection or spring rate that can affect measurement accuracy. A better understanding of spring rate can enable quality control inspectors to detect and eliminate this possible error source.
Even the old, reliable gage is subject to wear. George Schuetz, director of precision gages at Mahr inc., gives guidance for machinists to maintain their gages.
Why use a dial indicator with more than the needed range? A dial comparator offers less risk of misreading the dial without the cost of an electronic gage.