Product Description
Van Keuren Thread Plug Gage Assembly – GO/NOGO, 1-1/4-12 UNF 2B, Reversible Steel Construction
This used Van Keuren thread plug gage assembly is a precision inspection tool designed for GO/NOGO testing of 1-1/4-12 UNF (Unified Fine) internal threads with a 2B class of fit . Van Keuren is a respected American manufacturer of precision gages, serving the metrology and quality control industry .
Thread plug gages provide a complete check of internal thread dimensions. The GO member tests the low limit of the thread (minimum major and pitch diameter), while the NOGO member tests the upper limit (maximum pitch diameter). When the GO member enters the threaded hole and the NOGO member does not, the part meets the 2B class of fit specification .
The gage is constructed from high-quality 52100 tool steel, hardened to 60-62 HRC for excellent wear resistance and dimensional stability. This reversible design allows replacement of individual gage members without replacing the entire assembly when wear occurs .
Condition Note: This unit is untested and sold as-is. It may show signs of normal use such as minor surface wear or staining. No calibration certificate is included unless specified. If the GO/NOGO members are mounted on a handle, verify that they are secure before use.
Thread Specification Details
| Specification | Value |
|---|---|
| Thread Size | 1-1/4 – 12 UNF |
| Class of Fit | 2B (internal thread, medium tolerance) |
| Thread Series | UNF (Unified Fine) |
| Nominal Diameter | 1.250 inches |
| Threads Per Inch | 12 TPI |
| Pitch | 0.083333 inches |
| GO Member Size | Minimum limit (low limit of product tolerance) |
| NOGO Member Size | Maximum limit (high limit of product tolerance) |
Thread Specification Explanation:
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1-1/4: Nominal major diameter of the thread (1.250 inches)
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12: Number of threads per inch
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UNF: Unified Fine thread series
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2B: Internal thread with standard commercial tolerance
Van Keuren Thread Plug Gage Features
| Feature | Benefit |
|---|---|
| 52100 Tool Steel Construction | High chrome content for corrosion resistance and reduced friction |
| 60-62 HRC Hardness | Optimal hardness for wear resistance without brittleness |
| Lapped Finish | Smooth, wear-resistant surface for long gaging life |
| Reversible Design | Individual gage members can be replaced as they wear |
| GO/NOGO Configuration | Complete quality verification in a single gage set |
| Class 2B Tolerance | Standard commercial fit for general purpose threads |
Gaging Principle :
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GO Gage: Must enter the full length of the threaded hole
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NOGO Gage: Must NOT enter more than 3 turns
-
Both tests must pass for the threaded hole to be accepted
Thread Gage Specifications
| Specification | Details |
|---|---|
| Manufacturer | Van Keuren (Willich Precision Instruments brand family) |
| Product Type | Thread Plug Gage Assembly |
| Gaging Type | GO / NOGO (double end) |
| Thread Size | 1-1/4-12 UNF |
| Class of Fit | 2B (internal thread) |
| Material | 52100 Tool Steel |
| Hardness | 60-62 HRC |
| Finish | Lapped surface |
| Design | Reversible (members can be replaced) |
| Handle Type | [Check if handle is included – double end reversible handle standard for this size] |
| Condition | Used – Untested |
Applications
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Manufacturing Quality Control: Inspection of threaded holes in production parts
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Machining Verification: Validating tapped hole dimensions in CNC operations
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Incoming Inspection: Checking purchased threaded components
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Tool and Die Making: Verifying thread dimensions in tooling applications
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Calibration Laboratories: Working standard for thread measurement
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Aerospace and Defense: Quality assurance for critical threaded connections
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Legacy System Support: Replacement gage for existing inspection protocols



