Threaded Ring Gauges with Calibration Certificate
Not only were these gauges calibrated in a lab, but they also come with a certificate that's traceable to NIST. The certificate, sometimes called a test report and long form certificate, details the tested measurements. They’re for checking a part’s external threads to ensure they fall within tolerance.
A part is within tolerance if it’s easy to thread a go gauge onto the part but difficult to thread a no-go gauge more than two turns. Inspect faster by holding more than one ring gauge with a threaded ring gauge holder.
Go gauges check the maximum external thread size.
No-go gauges check the minimum external thread size.
Threads have different classes of fit. Thread fit designates the tightness or looseness of the mating threads. For example, inch threads with a 3A fit have tighter tolerances than threads with a 2A fit.
| Thread Size  | Thread Type | Thread Direction | Hardness | Material | Pitch Dia. Tolerance | Each | |
Go Gauge | |||||||
|---|---|---|---|---|---|---|---|
For Thread Fit Class 2A | |||||||
| 12-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A412 | 0000000 |
| 1/4"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A416 | 000000 |
| 5/16"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A421 | 000000 |
| 3/8"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A425 | 000000 |
| 7/16"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A429 | 000000 |
| 1/2"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A434 | 000000 |
| 9/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A438 | 000000 |
| 5/8"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A443 | 000000 |
| 11/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A447 | 000000 |
| 3/4"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A452 | 000000 |
| 7/8"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A458 | 000000 |
| 1"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A467 | 000000 |
For Thread Fit Class 3A | |||||||
| 12-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A413 | 000000 |
| 1/4"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A417 | 000000 |
| 5/16"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A422 | 000000 |
| 3/8"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A426 | 000000 |
| 7/16"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A431 | 000000 |
| 1/2"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A435 | 000000 |
| 9/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A439 | 000000 |
| 5/8"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A444 | 000000 |
| 11/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A448 | 000000 |
| 3/4"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A453 | 000000 |
| 7/8"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 3160A459 | 000000 |
No-Go Gauge | |||||||
For Thread Fit Class 2A | |||||||
| 12-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A414 | 000000 |
| 1/4"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A418 | 000000 |
| 5/16"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A423 | 000000 |
| 3/8"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A427 | 000000 |
| 7/16"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A432 | 000000 |
| 1/2"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A436 | 000000 |
| 9/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A441 | 000000 |
| 5/8"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A445 | 000000 |
| 11/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A449 | 000000 |
| 3/4"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A454 | 000000 |
| 7/8"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A461 | 000000 |
| 1"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A468 | 000000 |
For Thread Fit Class 3A | |||||||
| 12-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A415 | 000000 |
| 1/4"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A419 | 000000 |
| 5/16"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A424 | 000000 |
| 3/8"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A428 | 000000 |
| 7/16"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A433 | 000000 |
| 1/2"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A437 | 000000 |
| 9/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A442 | 000000 |
| 5/8"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A446 | 000000 |
| 11/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A451 | 000000 |
| 3/4"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A455 | 000000 |
| 7/8"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 3160A462 | 000000 |
Threaded Ring Gauges
Check a part’s external threads to make sure they fall within tolerance. You can use these for bolts, threaded rods, bits, and more. All gauges come with a manufacturer’s certificate of accuracy, also known as a certificate of compliance or a short form certification, that verifies the thread sizes are within tolerance.
The part is within tolerance if it’s easy to thread a go gauge onto, but difficult to thread a no-go gauge more than two turns. Use a threaded ring gauge holder to keep two gauges on hand at once for faster inspection.
Go gauges check the maximum external thread size.
No-go gauges check the minimum external thread size.
Threads have different classes of fit. Thread fit designates the tightness or looseness of the mating threads. For example, inch threads with a 3A fit have tighter tolerances than threads with a 2A fit.
| Thread Size | Thread Type | Hardness | Material | Choose a For Thread Fit | Thread Direction | Pitch Dia. Tolerance | Each | |
Go Gauge | ||||||||
|---|---|---|---|---|---|---|---|---|
Class X | ||||||||
| 12-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 2356A019 | 0000000 | |
| 1/4"-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 2356A022 | 000000 | |
| 5/16"-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 2356A024 | 000000 | |
| 3/8"-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 2356A026 | 000000 | |
| 7/16"-28 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 2356A028 | 000000 | |
| 1/2"-28 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 2356A031 | 000000 | |
| 9/16"-24 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 2356A033 | 000000 | |
| 5/8"-24 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 2356A035 | 000000 | |
| 11/16"-24 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 2356A037 | 000000 | |
| 3/4"-20 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 2356A039 | 000000 | |
| 7/8"-20 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 2356A042 | 000000 | |
| 1"-20 | UNEF | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0003" to 0" | 2356A578 | 000000 |
No-Go Gauge | ||||||||
Class X | ||||||||
| 12-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 2356A021 | 000000 | |
| 1/4"-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 2356A023 | 000000 | |
| 5/16"-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 2356A025 | 000000 | |
| 3/8"-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 2356A027 | 000000 | |
| 7/16"-28 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 2356A029 | 000000 | |
| 1/2"-28 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 2356A032 | 000000 | |
| 9/16"-24 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 2356A034 | 000000 | |
| 5/8"-24 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 2356A036 | 000000 | |
| 11/16"-24 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 2356A038 | 000000 | |
| 3/4"-20 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 2356A041 | 000000 | |
| 7/8"-20 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 2356A043 | 000000 | |
| 1"-20 | UNEF | Rockwell C60 | Tool Steel | Class 2A | Right Hand | 0" to 0.0003" | 2356A579 | 000000 |