Inner Head Nut ONA-442.7918-01 suitable for Sandvik CH430 CS430 Cone Crusher

Product Overview
The inner head nut (also referred to as the inner headnut or locking nut) is a critical fastener positioned inside the head assembly of a cone crusher. It works together with the outer head nut to securely clamp the mantle onto the main shaft, ensuring that the crushing forces generated during operation are properly transmitted through the shaft system rather than being absorbed by the mantle alone. As a key component of the main shaft assembly, the inner head nut directly influences the stability, efficiency, and service life of the entire crusher.

The ONA‑442.7918‑01 inner head nut is precision‑engineered as a direct replacement part suitable for Sandvik CH430 and CS430 cone crushers, as well as their earlier equivalents H3800 and S3800. Weighing 8 kg and with a height of 77 mm, this component is manufactured to original equipment specifications, ensuring seamless integration with the crusher's existing head assembly. Every ONA inner head nut undergoes 100% dimensional inspection before shipment, guaranteeing a perfect fit and reliable performance under the most demanding crushing conditions.

Product Features

Precision‑Engineered Fit
The ONA‑442.7918‑01 inner head nut is manufactured to exact OEM tolerances, ensuring seamless compatibility with cone crushers suitable for Sandvik CH430 and CS430. The precision‑cut threads engage perfectly with the main shaft, eliminating any play or misalignment during installation.

High‑Strength Alloy Steel Construction
Made from premium alloy steel, the inner head nut is designed to withstand the extreme forces generated during secondary and tertiary crushing operations. The material provides excellent resistance to thread wear, fatigue cracking, and deformation under heavy loads.

Reliable Mantle Locking
As a critical fastener in the main shaft assembly, the inner head nut works in conjunction with the outer head nut to securely clamp the mantle in place. This dual‑nut design ensures that the mantle remains firmly positioned throughout the crushing cycle, eliminating axial movement that could compromise product consistency.

Long Service Life
The combination of high‑quality materials and precision machining ensures extended service life, reducing the frequency of replacement and lowering overall maintenance costs for crusher operators.

Function

Secures the Mantle

The inner head nut provides the primary clamping force that holds the mantle firmly onto the main shaft. This ensures that the mantle remains in its correct position during operation, preventing unwanted movement that could lead to uneven liner wear or reduced crushing efficiency.

Transmits Crushing Forces

By creating a rigid mechanical connection between the mantle and the main shaft, the inner head nut enables the efficient transmission of crushing forces throughout the shaft system. This ensures that the energy generated by the eccentric assembly is effectively transferred to the rock being crushed.

Maintains Assembly Integrity

The inner head nut works together with the outer head nut and other main shaft components to maintain the structural integrity of the entire head assembly. A properly torqued inner head nut prevents loosening during operation, reducing the risk of damage to other critical components such as the main shaft and head center

Applications

Secondary Crushing in Aggregate Production

Cone crushers suitable for Sandvik CH430 and CS430 are widely used in secondary crushing applications for aggregate production. The inner head nut plays a critical role in maintaining stable crushing performance, ensuring consistent product shape and gradation essential for high‑quality construction materials.

Tertiary and Pebble Crushing

In high‑reduction tertiary or pebble‑crushing applications, cone crushers suitable for Sandvik CH430 and CS430 operate under variable feed conditions. The inner head nut ensures the mantle remains securely locked, delivering reliable performance even when processing abrasive materials.

Mobile Crushing Plants

Cone crushers suitable for Sandvik CH430 are integrated into various mobile crushing units such as the QH331 and UH440i. In mobile applications where equipment is frequently transported and set up, the inner head nut must withstand additional stresses from transportation and rapid deployment.

FAQs

Q1: Is the ONA‑442.7918‑01 inner head nut a direct replacement for the original part on cone crushers suitable for Sandvik CH430?

Yes. The ONA‑442.7918‑01 inner head nut is manufactured to OEM specifications, making it a direct‑fit replacement for cone crushers suitable for Sandvik CH430 and CS430, as well as H3800 and S3800 models. It requires no modifications during installation. Please confirm your crusher model and original part number before ordering to ensure correct fitment.

Q2: What is the difference between the inner head nut and the outer head nut?

The inner head nut is installed inside the head assembly and works together with the outer head nut to clamp the mantle onto the main shaft. The outer head nut, often supplied with a burning ring, provides additional locking force and is typically replaced along with the inner head nut during major maintenance. Both nuts are essential for maintaining proper mantle positioning.

Q3: How often should the inner head nut be inspected or replaced?

The inner head nut should be inspected during every mantle change and during routine maintenance intervals. Common signs of wear include thread damage, deformation, or visible cracks. ONA recommends replacing the inner head nut if any damage is detected. Keeping a spare inner head nut in stock helps minimize downtime during scheduled or emergency maintenance.