BIS for Hexagon Nuts Grade C IS 1363 (Part 3) :2018

IS 1363 (Part 3):2018 is the Indian Standard which provides the specifications of Hexagon Nuts (Type 1) having product grade C within the size range of M5-M64. IS 1363:2018 specifies dimensions, tolerance, thread, material, mechanical and performance requirements to provide uniformity in the interchangeability and performance of the fasteners. Evaluation criteria of Hexagon nuts as per BIS include:

• Dimensional accuracy and tolerance requirements
• Thread profile and thread fit verification
• Mechanical strength and proof load performance
• Material composition and hardness properties
• Surface finish and corrosion protection characteristics

• Domestic Manufacturers - Must obtain BIS certification before supplying products in India
• Foreign Manufacturers - Required to secure BIS approval before exporting to the Indian market
• Importers and Brand Owners - Responsible for sourcing compliant and certified products
• Industrial Suppliers and Distributors - Must ensure certified products are supplied for commercial applications

• Meets IS 1363 (Part 3):2018 specifications
• Improves reliability of fastening process
• Improves joint strength
• Improves compatibility with bolts and screws
• Minimizes chances of threads breaking and loosening
• Suitable for use in government and infrastructure works
• Improves consistency and quality of products
• Improves consumer confidence and company's reputation in the market
• Increases acceptability in both domestic and international markets

• R (Required): Test must be done in the manufacturer’s own lab
• S (Subcontracting Allowed):Test can be done in an external BIS-approved lab

• Proof Load Test (R)—Ensures the nut can withstand specified load without deformation
• Hardness Test (R) – Verifies hardness level for strength and durability
• Material Property Test (S) – Ensures the material meets required standards

• Dimension Test (R) – Ensures correct size and geometry as per standard
• Thread Accuracy Test (R) – Verifies proper threading for correct fit with bolts
• Tolerance Test (R) – Ensures dimensions are within permissible limits

• Electroplating Test (R) – Checks coating quality and thickness
• Zinc Flake Coating Test (R) – Ensures proper protective coating performance
• Finish Inspection (R) – Ensures smooth, defect-free surface

• Surface Integrity Test (R) – Detects cracks or defects in the nut structure
• Visual Inspection (R) – Ensures no visible defects or imperfections

1. Online Registration: Manufacturers register on the BIS Manak portal by submitting company, factory, and product details. Foreign manufacturers must appoint an Authorized Indian Representative (AIR).
2. Testing at BIS-Approved Laboratory: Product samples are tested in BIS-approved labs to check safety, insulation, heating performance, and electrical protection.
3. Application Submission: The application is submitted along with test reports, technical documents, and factory details. Foreign manufacturers must also submit AIR-related documents.
4. Factory Inspection: BIS officials inspect the manufacturing unit to verify the production process, safety measures, and quality control system.
5. Grant of BIS License: If all requirements are met, BIS grants the certification license under Scheme-I.
6. Use of ISI Mark: After approval, the manufacturer can use the ISI mark on products with a CM/L number, confirming that the product meets BIS standards.