Specification summary of ISO 1502 as applied to thread plug and ring gauges: the dimensions the standard fixes, the full size range supplied, and the related designations commonly cross-referenced.
ISO 1502 — Scope
The table below lists the dimensions catalogued for thread plug and ring gauges under ISO 1502. The scope of ISO 1502 itself is not summarised here — where a figure matters, confirm it against the published document.
Tolerance & Product Grades
Product grade is a concept from dimensional fastener standards and does not apply to ISO 1502. Tolerances for this part are the limits shown against each dimension in the table.
Dimensions Specified by ISO 1502
| Gauge | Checks | GO member | NO-GO member |
|---|---|---|---|
| thread plug gauge | internal thread (nuts, tapped holes) | must screw fully in | must not enter beyond two turns |
| thread ring gauge | external thread (bolts, studs) | must screw fully on | must not engage beyond two turns |
| plain plug gauge | drilled hole size before tapping | must enter | must not enter |
| tolerance class 6H | internal thread fit | standard commercial nut thread | standard commercial nut thread |
| tolerance class 6g | external thread fit | standard commercial bolt thread | standard commercial bolt thread |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Thread Plug and Ring Gauges page.
Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
Companion Standards
A complete specification for thread plug and ring gauges normally cites several documents: one for the geometry, one for the material or mechanical properties, and one for the finish. ISO 1502 is one of them, not all of them.
Custom manufacturing · Made to drawing
Need a fastener tool to this standard in a non-standard size?
Parts built to ISO 1502 are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
