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
A certificate of calibration traceable to NIST states that these gauges have passed a test for accuracy. 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.
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.
For technical drawings and 3-D models, click on a part number.
Inch
Go Gauge | |||||||
|---|---|---|---|---|---|---|---|
Class 2A | Class 3A | ||||||
Thread Size | Thread Type | Hardness | Material | Each | Each | ||
Class X | |||||||
| 0-80 | UNF | Rockwell C60 | Tool Steel | 00000000 | 0000000 | 00000000 | 0000000 |
| 1-64 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 1-72 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 2-56 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 2-64 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 3-48 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 4-40 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 4-48 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 5-40 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 6-32 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 6-40 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 8-32 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 8-36 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 10-24 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 10-32 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 12-24 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 12-28 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 1/4"-20 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 1/4"-28 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 5/16"-18 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 5/16"-24 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 3/8"-16 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 3/8"-24 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 7/16"-14 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 7/16"-20 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 1/2"-13 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 1/2"-20 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 9/16"-18 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 5/8"-11 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 5/8"-18 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 3/4"-10 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 3/4"-16 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 7/8"-9 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 7/8"-14 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 1"-8 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 1"-12 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 1"-14 | UNS | Rockwell C60 | Tool Steel | 000000 | 00 | 00000000 | 000000 |
| 1 1/8"-12 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 1 1/4"-7 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 1 1/4"-12 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 1 1/2"-12 | UNF | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
| 1 1/2"-6 | UNC | Rockwell C60 | Tool Steel | 00000000 | 000000 | 00000000 | 000000 |
Metric
Go Gauge | ||||||
|---|---|---|---|---|---|---|
Class 6g | ||||||
| Thread Size | Thread Type | Pitch | Hardness | Material | Each | |
Class X | ||||||
| M1.6 | Metric | 0.35 mm | Rockwell C60 | Tool Steel | 00000000 | 0000000 |
| M2 | Metric | 0.4 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M2.5 | Metric | 0.45 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M3 | Metric | 0.5 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M3.5 | Metric | 0.6 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M4 | Metric | 0.7 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M5 | Metric | 0.8 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M6 | Metric | 1 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M7 | Metric | 1 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M8 | Metric | 1 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M8 | Metric | 1.25 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M10 | Metric | 1.25 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M10 | Metric | 1.5 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M12 | Metric | 1 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M12 | Metric | 1.25 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M12 | Metric | 1.5 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M12 | Metric | 1.75 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M14 | Metric | 1.5 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M16 | Metric | 1.5 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M16 | Metric | 2 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
| M18 | Metric | 1.5 mm | Rockwell C60 | Tool Steel | 00000000 | 000000 |
Threaded Ring Gauges
Check a part’s external threads to ensure they fall within tolerance.
The 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.
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.
For technical drawings and 3-D models, click on a part number.
Inch
Go Gauge | |||||||
|---|---|---|---|---|---|---|---|
| Thread Size | Thread Type | Hardness | Material | Choose a For Thread Fit | Pitch Dia. Tolerance | Each | |
Class X | |||||||
| 0-80 | UNF | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 0000000 | |
| 1-72 | UNF | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 | |
| 2-56 | UNC | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 | |
| 3-48 | UNC | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 | |
| 4-40 | UNC | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 | |
| 4-48 | UNF | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 | |
| 5-40 | UNC | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 | |
| 6-32 | UNC | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 6-40 | UNF | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 | |
| 8-32 | UNC | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 8-36 | UNF | Rockwell C60 | Tool Steel | -0.0002" to 0" | 00000000 | 000000 | |
| 10-24 | UNC | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 10-32 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 12-24 | UNC | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 1/4"-20 | UNC | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 1/4"-28 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 5/16"-18 | UNC | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 5/16"-24 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 3/8"-16 | UNC | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 3/8"-24 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 7/16"-14 | UNC | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 7/16"-20 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 1/2"-13 | UNC | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 1/2"-20 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 9/16"-18 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 5/8"-11 | UNC | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 5/8"-18 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 3/4"-10 | UNC | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 3/4"-16 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 7/8"-9 | UNC | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 7/8"-14 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 1"-8 | UNC | Rockwell C60 | Tool Steel | -0.0004" to 0" | 00000000 | 000000 | |
| 1"-12 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 1"-14 | UNS | Rockwell C60 | Tool Steel | Class 3A | -0.0003" to 0" | 00000000 | 000000 |
| 1 1/8"-12 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
| 1 1/4"-7 | UNC | Rockwell C60 | Tool Steel | -0.0004" to 0" | 00000000 | 000000 | |
| 1 1/4"-12 | UNF | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 | |
Metric
Go Gauge | |||||||
|---|---|---|---|---|---|---|---|
| Thread Size | Pitch | Hardness | Material | For Thread Fit | Pitch Dia. Tolerance | Each | |
Class X | |||||||
| M1.6 | 0.35 mm | Rockwell C60 | Tool Steel | Class 6g | -0.005mm to 0mm | 000000000 | 0000000 |
| M2 | 0.4 mm | Rockwell C60 | Tool Steel | Class 6g | -0.005mm to 0mm | 000000000 | 000000 |
| M2.5 | 0.45 mm | Rockwell C60 | Tool Steel | Class 6g | -0.005mm to 0mm | 000000000 | 000000 |
| M3 | 0.5 mm | Rockwell C60 | Tool Steel | Class 6g | -0.005mm to 0mm | 000000000 | 000000 |
| M3.5 | 0.6 mm | Rockwell C60 | Tool Steel | Class 6g | -0.005mm to 0mm | 000000000 | 000000 |
| M4 | 0.7 mm | Rockwell C60 | Tool Steel | Class 6g | -0.005mm to 0mm | 000000000 | 000000 |
| M5 | 0.8 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 00000000 | 000000 |
| M6 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 000000000 | 000000 |
| M8 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 00000000 | 000000 |
| M8 | 1.25 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 000000000 | 000000 |
| M10 | 1.25 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 000000000 | 000000 |
| M10 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 000000000 | 000000 |
| M12 | 1 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 000000000 | 000000 |
| M12 | 1.25 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 00000000 | 000000 |
| M12 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 000000000 | 000000 |
| M12 | 1.75 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 000000000 | 000000 |
| M14 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 000000000 | 000000 |
| M16 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 000000000 | 000000 |
| M16 | 2 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 000000000 | 000000 |
| M18 | 1.5 mm | Rockwell C60 | Tool Steel | Class 6g | -0.008mm to 0mm | 000000000 | 000000 |