This document specifies the fundamental deviations and limits of sizes for the pitch and minor diameters of ISO general purpose metric internal threads (M) conforming to ISO 262 (M6 to M68 with the coarse pitches and M72 to M100 with pitch 6) having basic and design profiles in accordance with ISO 68‑1.

This document is applicable to the metric internal threads oversized to tolerance class 6AZ or 6AX to mate with the hot-dip galvanized external threads with maximum size of tolerance position h before galvanizing.

This document is not applicable to internal threads with coating on thread surface. The limits of sizes before coating are decided by agreement between manufacturer and purchaser.