British Standards Institution

Source:: ISO
Committee:: ACE/12 - Aerospace fasteners and fastening systems
Categories:: Information management | Standardization. General rules
Comment period start date:: 10/06/2025
Comment period end date:: 02/08/2025

Comment by:

2nd Aug

Scope

This standard describes the dimensions of hexagonal head bolts, with large tolerance normal shank and UNJF threads, in metallic material (alloy steel, CRES and titanium alloy, etc.), coated or uncoated. It is applicable to be used as a test bolt for torque-tension tests of self-locking nuts and threaded collars to determine locking torque, breakaway torque and preload.

Purpose

High demand for the aerospace fastener industry, OEMs and laboratories. Various tests have been performed as a basis for the test bolt definition, and the test bolt standard for metric (MJ) threads has been published (ISO 6397) in 2024. This new standard will be complementary to ISO 6397, focusing on imperial (UNJF) threads.

Comment on proposal

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Discard

Please email further comments to: debbie.stead@bsigroup.com

Standard timeline

1. Proposal

Proposal start date:

10/06/2025

Proposal end date:

02/08/2025

2. Draft

3. Public Comments

4. Comment Resolution

5. Approval

6. Publication

Learn more about the standards development process

Standards Development

ISO/NP 25963 Aerospace — Test bolts, hexagonal head, UNJF threads, metallic material, coated or uncoated

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