Description and Specification for Lab Tenders
Crackness Tester Machines.
The resistance to cracking of the grain of a leather sample and its crack index are determined by taking a rectangular strip from the sample of leather under test and bending it around a cylindrical mandrel while maintaining the two in close contact. The test specimen is successively bent over mandrels of diminishing diameters to produce successively higher degree of extension in its outer grains till cracks start appearing on its outer surface. The diameter of mandrel over which the crack is first observed gives the measure of the resistance to cracking and crack index of the sample under test.