Thread Gauges
Völkel threading tools
Thread gauges check finished threads for dimensional accuracy to DIN ISO 1502. Testing follows the limit gauge principle with a go gauge and a no go gauge: the go side must screw on by hand over the full thread length, the no go side may engage two turns at most. Internal threads are checked with a thread plug gauge, external threads with a thread ring gauge, the profile follows DIN 13 and ISO 68-1, and the tolerance class is marked on the gauge, commonly 6H for internal and 6g for external threads. The category holds 123 articles, 121 from Völkel and two replacement limit plug gauges from Knipex.
| Gauge type | Marking | Test object | Assessment |
|---|---|---|---|
| Thread plug gauge, go side | GO | internal thread | must screw on over the full length |
| Thread plug gauge, no go side | NOGO | internal thread | may engage two turns at most |
| Thread ring gauge, go side | GO | external thread | must screw on over the full length |
| Thread ring gauge, no go side | NOGO | external thread | may engage two turns at most |
Typical applications: incoming inspection of bought in threaded parts; production control after tapping in series manufacture; release of threads after surface treatment such as galvanising or painting; checking repaired threads after a thread insert has been fitted; calibration cycles and test equipment monitoring in quality assurance.
