Technical Information
Gaging Fundamentals
Fixed limit gages are highly accurate, easy-to-use tools designed to verify geometries and dimensions. They ensure that a part’s dimensions fall within its specified tolerance limits, confirming whether the part is acceptable or unacceptable based on required specifications. These gages provide a reliable method for ensuring that finished parts meet quality standards and are built to spec.
Tolerance 10% Rule is designed to guide the selection of the appropriate tolerance for Go/NoGo gages. This rule suggests that if you allocate 10% of the total product tolerance to the gages, you can confidently inspect 90% of your product tolerance 100% of the time.
TYPES OF GAGES
Class XX Pin Gages
- Tolerance (Inch): ± .000020″
- Tolerance (Metric): ± .00051mm
Ideal for high-precision applications where tolerances are extremely tight, Class XX Pin Gages offer unparalleled accuracy, making them suitable for critical dimensions.
Class X Pin Gages
- Tolerance (Inch): ± .000040″
- Tolerance (Metric): ± .00102mm
Used when greater precision is needed, Class X Pin Gages provide a high level of accuracy for various precision applications.
Class Y Pin Gages
- Tolerance (Inch): ± .000070″
- Tolerance (Metric): ± .00178mm
Designed for applications requiring moderate precision, Class Y Pin Gages offer a balance between accuracy and practicality.
Note: Only available for TriLocks, TaperLocks, Ring Gages, Progressives, and Master Setting Discs.
Class Z Pin Gages
- Tolerance (Inch): ± .0001″
- Tolerance (Metric): ± .00245mm
With half the deviation of Class ZZ Gages, Class Z Pin Gages ensure a better fit where enhanced precision is required.
Class ZZ Pin Gages
- Tolerance (Inch): ± .0002″
- Tolerance (Metric): ± .00508mm
Practical for situations where precision and speed are both important, Class ZZ Pin Gages are a versatile choice.
Note: Available only in Custom Length Pins.
Go/NoGo Gages
- Go Gage: Used to verify that the hole meets the lower tolerance limit.
- NoGo Gage: Used to verify that the hole does not exceed the upper tolerance limit
Go/NoGo Gages are essential for determining the lower and upper limits of a hole’s dimensions.
These gages are valuable for precisely measuring hole sizes and depths, checking hole location and distances, and setting micrometers.
Ring Gages
- Go Ring Gage: Checks the minimum acceptable diameter.
- NoGo Ring Gage : Ensures the part does not exceed the maximum diameter.
Ring Gages are used to gage outside diameters and are commonly available in hardened steel. Typically used in pairs:
Though often used for taper and spline checking, Ring Gages can also be used to set Bore Gages. They are ideal for confirming exact outside diameters when precise measurements are critical.
Application For Plug Gages
Go Gage (Minimum Diameter of Hole)
Apply the tolerance Plus on the Go plug. If the Go plug passes through the hole, it confirms the hole is larger than the required minimum diameter.
If the tolerance is applied Minus on the Go plug, there is a risk of accepting product that is below the minimum required diameter.
If the tolerance is applied minus on the Go plug, there is a risk of accepting product that is below the minimum required diameter.
NoGo Gage (Maximum Diameter of Hole)
Apply the tolerance Minus on the NoGo Plug. If the NoGo Plug does not enter the hole, it confirms that the hole diameter is smaller than the maximum allowed diameter and within tolerance.
If the tolerance applied is Plus on the NoGo plug, there is a risk of accepting product that exceeds the maximum diameter of the hole.
This page provides a clear breakdown of how to apply the Gage Tolerance 10% Rule to ensure precise and reliable product inspections. If you need further assistance with gage selection or tolerance guidelines, feel free to contact us.
Gage Maintenance
The proper care and maintenance of your gages are essential to ensure accurate and reliable measurements. Follow these guidelines to maximize the lifespan of your gages and maintain precision in your operations:
Cleanliness of Dimensions
- Ensure that all dimensions to be gaged, including threaded holes, are clean and free of any burrs or debris before use.
- Keeping surfaces clean helps prevent false readings and damage to the gage.
Slow, Careful Fit
- Turn gages slowly into or onto the part being measured, allowing for a snug fit without applying excessive force.
- Keeping surfaces clean helps prevent false readings and damage to the gage.
Protect from Environmental Factors
- Shield your gages from excessive heat, moisture, and corrosive chemicals.
- Environmental factors can degrade the material of the gage, compromising its accuracy and longevity.
Control Temperature Variations
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Ensure that the gage and the part being measured are at the same temperature.
- Differences in temperature can cause thermal expansion, affecting the accuracy of the measurement.
Regular Calibration
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- Calibrate your gages periodically to maintain precision.
- The frequency of calibration depends on several factors:
- How often the gage is used
- The tolerance levels it must
- The abrasiveness ensures your gages remain reliable and accurate.
Regular calibration ensures your gages remain reliable and accurate.