Calibration Samples
Test sieves calibration samples supplied by Endecotts are microspheres formed of soda-lime glass that range from 3.35 mm down to 20 microns. Because of the precise nature and extent of the range of spheres, samples can be supplied to enable the accurate calibration of individual sieves to an accuracy of approx +/- 1µm.

The microspheres pass over, almost, the total surface of the sieve enabling more apertures to be examined than with any other method.
Consequently, calibration samples are one of the most accurate methods of sieve calibration available.