Ring Gauges for Outside Diameters
Check the outside diameter of shafts, rods, and other cylindrical objects to determine whether they’re in tolerance.
If your part can pass through a go gauge but cannot pass through a no-go gauge, it is within tolerance.
Go gauges check the maximum outside diameter.
For technical drawings and 3-D models, click on a part number.
Go Gauges | |||||||
|---|---|---|---|---|---|---|---|
| Choose a Size | Increment | Surface Smoothness (RMS), microinch | Hardness | Material | Gauge Tolerance | Each | |
Class Z | |||||||
| 0.1501" to 0.2400" | 0.0001" | 8 | Rockwell C60 | Tool Steel | -0.0001" to 0" | 0000000 | 0000000 |
| 0.2401" to 0.3650" | 0.0001" | 8 | Rockwell C60 | Tool Steel | -0.0001" to 0" | 0000000 | 000000 |
| 0.3651" to 0.5100" | 0.0001" | 8 | Rockwell C60 | Tool Steel | -0.0001" to 0" | 0000000 | 000000 |
| 0.5101" to 0.8250" | 0.0001" | 8 | Rockwell C60 | Tool Steel | -0.0001" to 0" | 0000000 | 000000 |
| 0.8251" to 1.1350" | 0.0001" | 8 | Rockwell C60 | Tool Steel | -0.00012" to 0" | 0000000 | 000000 |
| 1.1351" to 1.5100" | 0.0001" | 8 | Rockwell C60 | Tool Steel | -0.00012" to 0" | 0000000 | 000000 |
| 1.5101" to 2.0100" | 0.0001" | 8 | Rockwell C60 | Tool Steel | -0.00016" to 0" | 0000000 | 000000 |
| 2.0101" to 2.5100" | 0.0001" | 8 | Rockwell C60 | Tool Steel | -0.00016" to 0" | 0000000 | 000000 |
Class X | |||||||
| 0.1501" to 0.2400" | 0.0001" | 4 | Rockwell C60 | Tool Steel | -0.00004" to 0" | 0000000 | 000000 |
| 0.2401" to 0.3650" | 0.0001" | 4 | Rockwell C60 | Tool Steel | -0.00004" to 0" | 0000000 | 000000 |
| 0.3651" to 0.5100" | 0.0001" | 4 | Rockwell C60 | Tool Steel | -0.00004" to 0" | 0000000 | 000000 |
| 0.5101" to 0.8250" | 0.0001" | 4 | Rockwell C60 | Tool Steel | -0.00004" to 0" | 0000000 | 000000 |
| 0.8251" to 1.1350" | 0.0001" | 4 | Rockwell C60 | Tool Steel | -0.00006" to 0" | 0000000 | 000000 |
| 1.1351" to 1.5100" | 0.0001" | 4 | Rockwell C60 | Tool Steel | -0.00006" to 0" | 0000000 | 000000 |
| 1.5101" to 2.0100" | 0.0001" | 4 | Rockwell C60 | Tool Steel | -0.00008" to 0" | 0000000 | 000000 |
| 2.0101" to 2.5100" | 0.0001" | 4 | Rockwell C60 | Tool Steel | -0.00008" to 0" | 0000000 | 000000 |
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.
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.
Inch—Class X
Go Gauge | |||||||
|---|---|---|---|---|---|---|---|
Thread Size | Thread Type | Thread Direction | Hardness | Material | Pitch Dia. Tolerance | Each | |
For Thread Fit Class 2A | |||||||
| 0-80 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 0000000 |
| 1-64 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 1-72 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 2-56 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 2-64 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 3-48 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 3-56 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 4-40 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 4-48 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 5-40 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 5-44 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 6-32 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 6-40 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 8-32 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 8-36 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 10-24 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 10-32 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 12-24 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 12-28 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 12-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1/4"-20 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1/4"-28 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1/4"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 5/16"-18 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 5/16"-24 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 5/16"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 3/8"-16 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 3/8"-24 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 3/8"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 7/16"-14 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 7/16"-20 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 7/16"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1/2"-13 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1/2"-20 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1/2"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 9/16"-12 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 9/16"-18 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 9/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 5/8"-11 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 5/8"-18 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 5/8"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 11/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 3/4"-10 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 3/4"-16 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 3/4"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 7/8"-9 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 7/8"-14 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 7/8"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1"-8 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1"-12 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1"-14 | UNS | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1 1/8"-7 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0004" to 0" | 00000000 | 000000 |
| 1 1/8"-12 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1 1/4"-7 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0004" to 0" | 00000000 | 000000 |
| 1 1/4"-12 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1 3/8"-6 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0004" to 0" | 00000000 | 000000 |
| 1 3/8"-12 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1 1/2"-6 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0004" to 0" | 00000000 | 000000 |
| 1 1/2"-12 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
For Thread Fit Class 3A | |||||||
| 0-80 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 1-72 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 2-56 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 2-64 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 3-56 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 4-40 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 4-48 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 5-40 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 5-44 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 6-32 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 6-40 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 8-32 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 8-36 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 |
| 10-24 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 10-32 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 12-28 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 12-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1/4"-20 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1/4"-28 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1/4"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 5/16"-18 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 5/16"-24 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 5/16"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 3/8"-16 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 3/8"-24 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 3/8"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 7/16"-20 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 7/16"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1/2"-13 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1/2"-20 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1/2"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 9/16"-18 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 9/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 5/8"-11 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 5/8"-18 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 5/8"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 11/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 3/4"-10 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 3/4"-16 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 3/4"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 7/8"-9 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 7/8"-14 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 7/8"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1"-12 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1"-14 | UNS | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1 1/8"-12 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1 1/4"-12 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1 3/8"-12 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
| 1 1/2"-6 | UNC | Right Hand | Rockwell C60 | Tool Steel | -0.0004" to 0" | 00000000 | 000000 |
| 1 1/2"-12 | UNF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
Metric—Class X
Go Gauge | |||||||
|---|---|---|---|---|---|---|---|
| Thread Size | Pitch | Thread Direction | Hardness | Material | Pitch Dia. Tolerance | Each | |
For Thread Fit Class 6g | |||||||
| M1.6 | 0.35 mm | Right Hand | Rockwell C60 | Tool Steel | -0.005 mm to 0 mm | 00000000 | 0000000 |
| M2 | 0.4 mm | Right Hand | Rockwell C60 | Tool Steel | -0.005 mm to 0 mm | 00000000 | 000000 |
| M2.2 | 0.45 mm | Right Hand | Rockwell C60 | Tool Steel | -0.005 mm to 0 mm | 00000000 | 000000 |
| M2.5 | 0.45 mm | Right Hand | Rockwell C60 | Tool Steel | -0.005 mm to 0 mm | 00000000 | 000000 |
| M3 | 0.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.005 mm to 0 mm | 00000000 | 000000 |
| M3.5 | 0.6 mm | Right Hand | Rockwell C60 | Tool Steel | -0.005 mm to 0 mm | 00000000 | 000000 |
| M4 | 0.7 mm | Right Hand | Rockwell C60 | Tool Steel | -0.005 mm to 0 mm | 00000000 | 000000 |
| M4.5 | 0.75 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M5 | 0.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.005 mm to 0 mm | 00000000 | 000000 |
| M5 | 0.8 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M6 | 0.75 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M6 | 1 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M7 | 1 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M8 | 0.75 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M8 | 1 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M8 | 1.25 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M9 | 1 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M9 | 1.25 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M10 | 1 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M10 | 1.25 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M10 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M11 | 1 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M11 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M12 | 1 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M12 | 1.25 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M12 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M12 | 1.75 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M14 | 1 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M14 | 1.25 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M14 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M14 | 2 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M16 | 1 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M16 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M16 | 2 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M18 | 1 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M18 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M18 | 2.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M20 | 1 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M20 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M20 | 2.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M22 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M22 | 2.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M24 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M24 | 2 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M24 | 3 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M26 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M27 | 2 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M27 | 3 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M30 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M30 | 2 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M30 | 3.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M33 | 2 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M33 | 3.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M35 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M36 | 1.5 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M36 | 2 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 000000 |
| M36 | 4 mm | Right Hand | Rockwell C60 | Tool Steel | -0.008 mm to 0 mm | 00000000 | 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.
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.
Inch
Go Gauge | ||||||||
|---|---|---|---|---|---|---|---|---|
| Thread Size | Thread Type | Hardness | Material | Choose a For Thread Fit | Thread Direction | Pitch Dia. Tolerance | Each | |
Class X | ||||||||
| 0-80 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0002" to 0" | 00000000 | 0000000 | |
| 1-64 | UNC | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0002" to 0" | 00000000 | 000000 |
| 1-72 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0002" to 0" | 00000000 | 000000 | |
| 2-56 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0002" to 0" | 00000000 | 000000 | |
| 2-64 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0002" to 0" | 00000000 | 000000 | |
| 3-48 | UNC | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0002" to 0" | 00000000 | 000000 |
| 3-56 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0002" to 0" | 00000000 | 000000 | |
| 4-40 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0002" to 0" | 00000000 | 000000 | |
| 4-48 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0002" to 0" | 00000000 | 000000 | |
| 5-40 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0002" to 0" | 00000000 | 000000 | |
| 5-44 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0002" to 0" | 00000000 | 000000 | |
| 6-32 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 6-40 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0002" to 0" | 00000000 | 000000 | |
| 8-32 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 8-36 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0002" to 0" | 00000000 | 000000 | |
| 10-24 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 10-32 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 12-24 | UNC | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0003" to 0" | 00000000 | 000000 |
| 12-28 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 12-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 1/4"-20 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 1/4"-28 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 1/4"-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 5/16"-18 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 5/16"-24 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 5/16"-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 3/8"-16 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 3/8"-24 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 3/8"-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 7/16"-14 | UNC | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0003" to 0" | 00000000 | 000000 |
| 7/16"-20 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 7/16"-28 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 1/2"-13 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 1/2"-20 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 1/2"-28 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 9/16"-12 | UNC | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0003" to 0" | 00000000 | 000000 |
| 9/16"-18 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 9/16"-24 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 5/8"-11 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 5/8"-18 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 5/8"-24 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 11/16"-24 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 3/4"-10 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 3/4"-16 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 3/4"-20 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 7/8"-9 | UNC | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 7/8"-14 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 7/8"-20 | UNEF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 1"-8 | UNC | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0004" to 0" | 00000000 | 000000 |
| 1"-12 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 1"-14 | UNS | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0003" to 0" | 00000000 | 000000 |
| 1"-14 | UNS | Rockwell C60 | Tool Steel | Class 3A | Right Hand | -0.0003" to 0" | 00000000 | 000000 |
| 1"-20 | UNEF | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0003" to 0" | 00000000 | 000000 |
| 1 1/8"-7 | UNC | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0004" to 0" | 00000000 | 000000 |
| 1 1/8"-12 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 1 1/4"-7 | UNC | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0004" to 0" | 00000000 | 000000 |
| 1 1/4"-12 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 1 1/2"-6 | UNC | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0004" to 0" | 00000000 | 000000 |
| 1 1/2"-12 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
| 1 3/8"-6 | UNC | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0004" to 0" | 00000000 | 000000 |
| 1 3/8"-12 | UNF | Rockwell C60 | Tool Steel | Right Hand | -0.0003" to 0" | 00000000 | 000000 | |
Metric
Go Gauge | ||||||||
|---|---|---|---|---|---|---|---|---|
| Thread Size | Pitch | Hardness | Material | For Thread Fit | Thread Direction | Pitch Dia. Tolerance | Each | |
Class X | ||||||||
| M1.6 | 0.35 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.005 mm to 0 mm | 000000000 | 0000000 |
| M2 | 0.4 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.005 mm to 0 mm | 000000000 | 000000 |
| M2.2 | 0.45 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.005 mm to 0 mm | 000000000 | 000000 |
| M2.5 | 0.45 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.005 mm to 0 mm | 000000000 | 000000 |
| M3 | 0.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.005 mm to 0 mm | 000000000 | 000000 |
| M3.5 | 0.6 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.005 mm to 0 mm | 000000000 | 000000 |
| M4 | 0.7 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.005 mm to 0 mm | 000000000 | 000000 |
| M4.5 | 0.75 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M5 | 0.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.005 mm to 0 mm | 000000000 | 000000 |
| M5 | 0.8 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 00000000 | 000000 |
| M6 | 0.75 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M6 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M7 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M8 | 0.75 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M8 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 00000000 | 000000 |
| M8 | 1.25 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M9 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M9 | 1.25 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M10 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M10 | 1.25 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M10 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M11 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M11 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M12 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M12 | 1.25 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 00000000 | 000000 |
| M12 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M12 | 1.75 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M14 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M14 | 1.25 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M14 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M14 | 2 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M16 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M16 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M16 | 2 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M18 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M18 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M18 | 2.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M20 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M20 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M20 | 2.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M22 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M22 | 2.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M24 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M24 | 2 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M24 | 3 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M26 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M27 | 2 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M27 | 3 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M30 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M30 | 2 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M30 | 3.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M33 | 2 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M33 | 3.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M35 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M36 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M36 | 2 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |
| M36 | 4 mm | Rockwell C60 | Tool Steel | Class 6g | Right Hand | -0.008 mm to 0 mm | 000000000 | 000000 |