Thread Check Inc. offers a full range of Master Discs which are ideal for calibrating and setting comparators, snap gages and other precision measuring instruments. Master discs are furnished with insulating grips to prevent heat distortion from handling. Master discs are available in gagemaker tolerances from class XX thru class Z. Master discs are offered in high quality tool steel, chrome, and carbide materials for longer life. All master discs provided are available in 3 styles for various applications. Master discs conform to ANSI B47.1. Master discs are ring lapped to size, and polished. Roundness and taper of all gages does not exceed 50% of the applicable gagemaker’s size tolerance and are non-accumulative. Master Discs sizes are available up to 23 inches in style #3. Contact Thread Check with any concerns you may have regarding master discs.