Straight mandrel and parallel mandrel are also called as inspection mandrels and are used for checking concentricity, parallelism and true running of components. Mandrel mounted between centers provides a reference straight line joining the two points (centers), so as to check the alignment of the centres. Parallel mandrels are made of hardened and stabilized steel. Mandrels are provided with properly ground and lapped centers for easy usage and accuracy.
Standard sizes and accuracy of Straight Mandrel and Parallel Mandrel As per IS-2063:1962.