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.
| 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" | 00000000 | 0000000 | |
| 1/4"-32 | UNEF | 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"-32 | UNEF | 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"-28 | UNEF | 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"-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"-20 | UNEF | 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"-20 | UNEF | Rockwell C60 | Tool Steel | Class 2A | Right Hand | -0.0003" to 0" | 00000000 | 000000 |
No-Go Gauge | ||||||||
Class X | ||||||||
| 12-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 00000000 | 000000 | |
| 1/4"-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 00000000 | 000000 | |
| 5/16"-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 00000000 | 000000 | |
| 3/8"-32 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 00000000 | 000000 | |
| 7/16"-28 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 00000000 | 000000 | |
| 1/2"-28 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 00000000 | 000000 | |
| 9/16"-24 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 00000000 | 000000 | |
| 5/8"-24 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 00000000 | 000000 | |
| 11/16"-24 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 00000000 | 000000 | |
| 3/4"-20 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 00000000 | 000000 | |
| 7/8"-20 | UNEF | Rockwell C60 | Tool Steel | Right Hand | 0" to 0.0003" | 00000000 | 000000 | |
| 1"-20 | UNEF | Rockwell C60 | Tool Steel | Class 2A | Right Hand | 0" to 0.0003" | 00000000 | 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.
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" | 00000000 | 0000000 |
| 1/4"-32 | UNEF | 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"-32 | UNEF | 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"-28 | UNEF | 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"-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"-20 | UNEF | 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"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | -0.0003" to 0" | 00000000 | 000000 |
For Thread Fit Class 3A | |||||||
| 12-32 | UNEF | 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"-32 | UNEF | 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"-28 | UNEF | 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"-24 | UNEF | 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"-20 | UNEF | 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 |
No-Go Gauge | |||||||
For Thread Fit Class 2A | |||||||
| 12-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 1/4"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 5/16"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 3/8"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 7/16"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 1/2"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 9/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 5/8"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 11/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 3/4"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 7/8"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 1"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
For Thread Fit Class 3A | |||||||
| 12-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 1/4"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 5/16"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 3/8"-32 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 7/16"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 1/2"-28 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 9/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 5/8"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 11/16"-24 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 3/4"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
| 7/8"-20 | UNEF | Right Hand | Rockwell C60 | Tool Steel | 0" to 0.0003" | 00000000 | 000000 |
Adjustable-Angle Quick-Response Threaded Thermometers
Obtain the best viewing angle and a fast response time with these pivoting thermometers filled with mercury-free fluid that registers temperature changes more quickly than dial thermometer stems. The case rotates 180° and the stem pivots 180° to support angled mounting. Tighten the set screws to secure the desired angle.
For technical drawings and 3-D models, click on a part number.
Stem | Material | Fluid | Thermometers | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temperature Range | Graduation Marks, ° F | Accuracy | Lg. | Dia. | Scale Ht. | Gender | Overall Ht. | Housing | Stem | Window | Material | Color | Thread Size | Thread Type | Each | |
| -40° to 110° F | 2° | ±2° F | 3 1/2" | 7/16" | 7" | Male | 15 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 000000 |
| -40° to 110° F | 2° | ±2° F | 3 1/2" | 7/16" | 9" | Male | 17 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| -40° to 110° F | 2° | ±2° F | 6" | 7/16" | 9" | Male | 20 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 0° to 160° F | 2° | ±2° F | 3 1/2" | 7/16" | 7" | Male | 15 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 0° to 160° F | 2° | ±2° F | 3 1/2" | 7/16" | 9" | Male | 17 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 0° to 160° F | 2° | ±2° F | 6" | 7/16" | 9" | Male | 20 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 20° to 180° F | 2° | ±2° F | 3 1/2" | 7/16" | 7" | Male | 15 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 20° to 180° F | 2° | ±2° F | 3 1/2" | 7/16" | 9" | Male | 17 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 20° to 180° F | 2° | ±2° F | 6" | 7/16" | 9" | Male | 20 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 30° to 240° F | 2° | ±2° F | 3 1/2" | 7/16" | 7" | Male | 15 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 30° to 240° F | 2° | ±2° F | 3 1/2" | 7/16" | 9" | Male | 17 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 30° to 240° F | 2° | ±2° F | 6" | 7/16" | 9" | Male | 20 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 30° to 300° F | 2° | ±2° F | 3 1/2" | 7/16" | 9" | Male | 17 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 30° to 300° F | 2° | ±2° F | 6" | 7/16" | 9" | Male | 20 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 30° to 300° F | 5° | ±2° F | 3 1/2" | 7/16" | 7" | Male | 15 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 50° to 400° F | 5° | ±2° F | 3 1/2" | 7/16" | 7" | Male | 15 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 50° to 400° F | 5° | ±2° F | 3 1/2" | 7/16" | 9" | Male | 17 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
| 50° to 400° F | 5° | ±2° F | 6" | 7/16" | 9" | Male | 20 3/4" | Aluminum | Zinc | Acrylic | Kerosene | Blue | 1 1/4"-18 | UNEF | 00000000 | 00000 |
Adjustable-Angle Solar-Powered Threaded Thermometers
Since these thermometers operate on indoor light, there’s no need for batteries. They pivot 180° to support angled mounting.
Attach the thermowell to protect thermometers from shock and pressure in tanks and pipelines.
For technical drawings and 3-D models, click on a part number.
Thermowell Attached | Thermowell Unattached | Material | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temperature Range | Resolution | Accuracy | Stem Length | Stem Dia. | Pipe Size | Thread Type | Stem Dia. | Thread Size | Thread Type | Gender | Max. Pressure | Overall Ht. | Housing | Stem | Each | |
Thermometer with Brass Thermowell | ||||||||||||||||
| -50° to 320° F/-45° to 160° C | 0.1/0.1 | ±1% | 3 1/2" | 5/8" | 3/4 | NPT | 7/16" | 1 1/4"-18 | UNEF | Male | Not Rated | 12 9/16" | Plastic | Aluminum | 0000000 | 0000000 |
| -50° to 320° F/-45° to 160° C | 0.1/0.1 | ±1% | 6" | 5/8" | 3/4 | NPT | 7/16" | 1 1/4"-18 | UNEF | Male | Not Rated | 15" | Plastic | Aluminum | 0000000 | 000000 |
Humidity-Indicating Plugs
Monitor humidity in sealed containers without opening them, protecting the inside from contamination. These plugs are often used on plastic bags, storage containers, and electrical housings. Consisting of a mounting nut and two gaskets for a tight seal, these plugs install through a hole in a flexible barrier. Remove one gasket and reverse the nut to install plugs in a rigid container. Watch the indicator disc through the nut’s viewing window—it will change color as humidity rises and falls. Made of anodized aluminum, these plugs resist corrosion and are lightweight. They meet military and SAE standards for humidity indicators.
For technical drawings and 3-D models, click on a part number.
Thread | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Humidity Points | Accuracy | Height | Width | For Hole Diameter | Type | Size | Indicator Use | Specifications Met | Each | |
Anodized Aluminum | ||||||||||
Spot-Style Indicator | ||||||||||
| 20%, 30%, 40%, 50% | ±5% | 5/8" | 1 7/8" | 1.45" | UNEF | 1 7/16"-18 | Reversible | MIL-I-8835; SAE AS26860 Type 2 | 0000000 | 000000 |