Overview
ISO 12125:2012 is an international standard that defines the specifications for prevailing torque type hexagon nuts with flange and non-metallic inserts, featuring metric fine pitch threads. The standard applies to style 2 nuts with nominal thread diameters ranging from 8 mm to 20 mm. It covers two product grades: Grade A for diameters up to 16 mm, and Grade B for diameters greater than 16 mm. These nuts come in property classes 6, 8, and 10, ensuring a range of mechanical strengths suitable for various engineering applications.
Prevailing torque hexagon nuts with flange are designed to provide reliable resistance to loosening under vibration and other dynamic loads, due to the integrated non-metallic insert which enhances the locking mechanism. The nuts specified in ISO 12125:2012 comply with tight dimensional and mechanical property requirements, making them ideal for critical fastening applications.
Key Topics
- Product Scope: Covers all-metal hexagon nuts with flange and a non-metallic insert, with metric fine pitch threads, style 2.
- Dimensions: Detailed thread and nut dimensions correspond to ISO 10663, with additional prevailing torque features specified.
- Grades and Property Classes:
- Product Grade A: For nut sizes with diameters ≤ 16 mm
- Product Grade B: For nut sizes with diameters > 16 mm
- Property Classes: 6, 8, 10 transverse mechanical strength ratings.
- Materials and Inserts: Nut bodies typically made from steel with polyamide or similar non-metallic inserts for prevailing torque.
- Thread Standards: Complies with ISO 261, ISO 724, and ISO 965-2 for metric fine pitch threads.
- Mechanical Requirements: Conformance to ISO 898-2 and ISO 2320 for mechanical and performance properties.
- Tolerance and Surface Finish:
- Gauging and Inspection: Uses specific gauges for dimensional checks, detailed in Annex A, ensuring compliance with standards.
- Designation Format: Clearly defined nut identification includes type, thread size, and property class (e.g., ISO 12125 - M12 × 1.5 - 8).
Applications
ISO 12125:2012 prevailing torque hexagon nuts with flange are vital components in industries requiring secure, vibration-resistant fasteners. Typical applications include:
- Automotive engineering – For engine assemblies and chassis components where fine pitch threads and secure fastening are critical.
- Aerospace and aviation – In structural components requiring high performance locking nuts that withstand vibration.
- Mechanical and industrial machinery – Use in precision equipment and assemblies needing fine thread pitch and reliable locking.
- Electrical and electronic equipment – Where controlled fastening torque and thread engagement prevent loosening.
- Construction and heavy machinery – Providing strong locking nuts for heavy-duty applications involving dynamic loads.
- General engineering – Any application requiring high-quality metric fine pitch fastening solutions with prevailing torque properties.
These nuts ensure safety, reliability, and consistent performance under demanding conditions thanks to strict adherence to ISO standards.
Related Standards
ISO 12125:2012 references and complements several key international standards to ensure interoperability and quality:
- ISO 10663 – Dimensions for hexagon nuts with flange.
- ISO 898-2 – Mechanical properties of nuts with specified property classes.
- ISO 2320 – Mechanical and performance properties of prevailing torque steel nuts.
- ISO 261, ISO 724, ISO 965-2 – Thread profile and tolerance specifications for metric fine pitch screws.
- ISO 4759-1 – Tolerances for fastener product grades.
- ISO 4042 and ISO 10683 – Electroplated and zinc flake coatings for fasteners.
- ISO 6157-2 – Surface discontinuity requirements to ensure quality.
- ISO 3269 – Acceptance inspection procedures for fasteners.
- ISO 8992 – General requirements for bolts, screws, studs, and nuts.
These interconnected standards support adherence to consistent quality, performance, and compatibility in fastening components worldwide.
Keywords: ISO 12125:2012, prevailing torque hexagon nuts, flange nuts, metric fine pitch thread, non-metallic insert, product grade A, product grade B, property classes 6 8 10, fastening standards, vibration-resistant nuts, ISO fasteners, industrial nuts, engineering nuts, metric nuts, locking nuts.
Open preview (PDF)Prevailing torque type hexagon nuts with flange (with non-metallic insert) with metric fine pitch thread, style 2 — Product grades A and B