Master Setting Ring For comparative gaging, calibration and the setting of internal measuring tools. Specifications include... 0.650" Size + 0.00006" Accuracy 0.000019" Taper / Ovality Features include... Made from oil hardened non-shrinking steel Hardened and tempered to 62 RC Actual dimensions duly etched Cryogenic treatment for long-term dimensional stability Calibrated at 20º C under standards room conditions
