Type 1 Hexagon Slotted Nuts and Castle Nuts (Fine Thread)— Product Introduction
Type 1 hexagon slotted nuts, also known as crown nuts, groove-type nuts, or bloom nuts, are fine-thread hexagon nuts manufactured in accordance with the GB/T 9457-1988 standard. They feature multiple radial slots machined into one end of the nut, which align with a pin hole at the end of a bolt. Once a cotter pin is inserted through the aligned holes, the nut is effectively prevented from loosening due to vibration, impact, or other factors. These nuts use metric fine-pitch threads and have a standard hexagonal shape, allowing installation and removal with ordinary wrenches. Depending on the required performance grade, the nuts are made from high-quality carbon structural steel (such as Grade 35 or Grade 45 steel) or alloy structural steel (such as 40Cr, 42CrMo, etc.). Surface treatments include blackening, zinc plating, phosphating, and more, making these nuts widely used in threaded connections that demand reliable anti-loosening performance.
I. Product Features
- End-face slotted structure: Multiple slots are machined into one end of the nut, allowing easy alignment with the bolt’s pin hole for cotter pin insertion, enabling mechanical anti-loosening.
- Fine-pitch threads: Metric fine-pitch threads with a smaller lead provide superior self-locking performance, making them ideal for thin-walled components and applications requiring anti-loosening.
- Hexagonal profile: Standard hexagonal design compatible with common ring spanners, open-end wrenches, or socket wrenches for easy installation and removal.
- Full range of materials and performance grades: Available in performance grades 8, 10, 12, and beyond, in both carbon steel and alloy steel to meet varying strength requirements.
- Multiple surface finishes: Common finishes include blackening, zinc plating, nickel plating, and phosphating to enhance corrosion resistance and appearance.
II. Product Advantages
- High anti-loosening reliability: When paired with a cotter pin, the nut is effectively secured against loosening under vibration, impact, or alternating loads, ensuring excellent safety.
- Reusable design: Only the cotter pin needs to be removed during disassembly; the nut itself remains largely undamaged, making it more suitable for repeated assembly and disassembly than nylon lock nuts.
- High standardization: Compliant with GB/T 9457, with uniform dimensions and excellent interchangeability; matching bolts are readily available.
- Ideal for fine-thread applications: Fine-pitch threads offer superior self-locking compared to coarse threads, making them suitable for thin-walled parts, adjustment components, and precision fastening structures.
- High load-bearing capacity: Made from medium-carbon or alloy steel with heat treatment, these nuts offer high strength and can withstand substantial preload and working loads.
III. Applications
- Automotive & Motorcycles: Wheel hub bearings, steering knuckles, suspension systems, and other locations requiring reliable anti-loosening.
- General Machinery Manufacturing: Threaded connections in machine tools, gearboxes, and transmission equipment that are subject to vibration and impact.
- Railway & Bridge Engineering: Rail fasteners, bridge steel structure connections, and other locations with stringent anti-loosening requirements.
- Construction Machinery: Critical fastening points in excavators, loaders, cranes, and other heavy-duty equipment.
- Shipbuilding & Marine Engineering: Threaded connections in marine equipment and deck machinery operating in vibrating and humid environments.
