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Top Lock Nut Grade C Zinc

From: $0.13

BoltCraft’s Top Lock Nut Grade C Zinc is engineered for secure fastening in demanding applications, incorporating a distinctive top lock feature with a robust zinc finish for exceptional durability and corrosion resistance.


$100 minimum order


  • Features an all-metal, one-piece design with a top lock mechanism that achieves its locking capability through the controlled distortion of the top threads, creating a more elliptical shape to resist loosening.
  • The zinc coating enhances corrosion resistance, making the nut suitable for a wide range of environments, especially where moisture or corrosive elements are present.

Applications & Advantages

  • Ideal for applications subject to severe vibration and shock loads, such as farm machinery, automotive assemblies, and metalworking industries, where secure fastening is critical.
  • The top lock design allows for reusability and withstands high temperatures up to 450°F, providing a durable solution in high-stress environments.
  • The Grade C lock nut reduces the need for additional locking mechanisms, streamlining the assembly process and ensuring a reliable hold even in demanding conditions.

Material & Specifications

  • Manufactured from high-quality C1022 – 1045 steel, ensuring strength and durability to withstand heavy loads and high stresses.
  • Heat treated to achieve a predominantly martensitic microstructure, with tempering to specified hardness levels, ensuring the nut’s integrity and performance.

Hardness & Durability

  • The nuts are designed to meet specific hardness requirements, with Rockwell hardness ratings of C24-C32 for sizes 1/4 through 5/8 inches, and C26-C34 for 3/4 through 1-inch sizes, ensuring optimal performance and resistance to deformation.
  • The top lock design, combined with high-quality steel and heat treatment, contributes to the nut’s overall durability, ensuring it maintains its locking capability and structural integrity over time.

Proof Load & Finish

  • These nuts are engineered to meet rigorous proof load standards, ensuring they can handle the specified loads without failure, contributing to the overall safety and reliability of the assembly.
  • The zinc plating not only provides a layer of protection against corrosion but also adds a clean, professional finish to the fastener, enhancing the aesthetic appeal of the assembled product.
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