How to find the right Calibration Setting Rings AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in Calibration Setting Rings
- Tolerance class
- Gagemaker classes under ASME B89.1.6, finest to coarsest: XXX, XX, X, Y, Z, ZZ. Class XX or X is the usual choice for setting bore gages. The ring's tolerance uses up part of your measurement budget, so it should be several times tighter than the bore tolerance you are checking.
- Certified actual size
- Buy with a calibration certificate that states the measured diameter (not just the nominal size), from an ISO/IEC 17025 accredited lab. You set the instrument to the ring's certified actual size, so an uncertified nominal-only ring defeats the purpose.
- Size match to instrument
- Nominal diameter must sit inside the range of the bore gage, three-point micrometer or internal micrometer head you are setting, ideally at or near the part's nominal bore. Setting near the measured size minimizes error from the instrument's linearity across its range.
- Material and wear resistance
- Choose hardened and stabilized tool steel for general use, and carbide or ceramic for heavy, frequent setting. The bore wears with every setting, and carbide or ceramic rings hold size much longer between recalibrations.
- Gaging length and finish
- Look for a lapped bore with a defined gaging zone. The ring should be wide enough for the gage's contact points to seat squarely. Narrow or poorly finished rings let the gage tilt or read surface roughness instead of size.
Brands that matter
- Mitutoyo: Supplies setting rings matched to its own bore gages and Holtest internal micrometers.
- Starrett: Offers master setting rings in common sizes, suited to general shop setting.
- Mahr: Precision setting rings aimed at its bore-gaging systems and QC labs.
- Fowler: Sells setting rings, often bundled with its bore gage kits, for budget shop use.
- Glastonbury Southern Gage: US gagemaker producing master and setting rings to ASME classes, including custom sizes.
- Westport: Makes plain and setting ring gages to gagemaker tolerance classes.
What to avoid
- Rings sold by nominal size only, with no certificate of actual size.
- Using a go/no-go inspection ring as a master for setting instruments.
- Rings with dings, rust or visible wear marks in the bore.
- Class Y, Z or ZZ rings for setting instruments that check tight-tolerance bores.
Questions
Is a setting ring the same as a go/no-go ring gage?
No. A setting ring is a certified master used to zero an instrument. A go/no-go ring is an inspection gage made to a limit of the part tolerance.
How often should a setting ring be recalibrated?
It depends on usage and your quality system. Frequently used steel rings need shorter intervals than carbide, so set the interval from wear history.