ユニファイねじリングゲージ 2aと3aの違いは？ | オーエスジー

Unified Thread Ring gauge What is the difference between 2A and 3A?

2A and 3A are the external thread accuracy ratings for unified threads.

 

2A: Widely used for general parts, equivalent to conventional JIS grade 2
3A: Strict grades equivalent to JIS 1 grade, which are common in aircraft-related parts and are equivalent to JIS 1 grade.

 

Since the pass range is different between 2A and 3A ring gauge , a external thread that passes with 3A ring gauge may fail with 2A ring gauge and cannot be shared.