The inherent problem of Centerless Grinding is the 3, 5 or 7 point lobing which occurs during the manufacturing stage. Most manufacturers simply proceed to lap their gauges for efficiency in size and finish. To the naked eye, the appearance of the final product is good. In reality however, the lobed segments are still present when observed under close magnification.
Add to that an improperly finished or unpolished gauging surface, and all you will be left with is a ‘precision’ measuring instrument that is in actuality, unfit for it’s intended purpose. The microscopic burrs that are present equate to highly inaccurate measurements as well as rapid wear and tear during your inspection process.