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Castle Nuts
Castle Nuts, also known as Castellated Nuts, are specially designed locking nuts with slots (castellations) on the top surface. These slots allow the use of a cotter pin or safety wire, ensuring positive locking and preventing loosening under vibration or dynamic loads. At UPS Lakshmi, we manufacture MS-standard Castle Nuts and Self-Locking Castellated Nuts such as MS17825, MS17826, and others suitable for demanding aerospace and high-reliability industrial assemblies. Key Features of Castle Nut Range
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Materials & Finishes
A286 Stainless Steel – High strength, corrosion resistant, heat resistant
AISI 4130 / 8740 Alloy Steel – High toughness and fatigue resistance
Surface Treatments:
Silver Plating
Passivation
Custom finishes as per customer requirement
Applications
Aircraft structural assemblies
Control systems & linkages
Landing gear mechanisms
Defence & aerospace hardware
High-vibration industrial systems
Why Choose UPS Lakshmi?
With over 65+ years of manufacturing expertise, UPS Lakshmi specialises in precision-engineered fasteners that meet stringent global standards. Our castle nuts are manufactured with tight dimensional control, consistent material quality, and proven reliability in demanding environments.
✔ Aerospace & automotive-grade quality
✔ Global standards compliance
✔ Custom sizes, materials & finishes available
Frequently Asked Questions About Castle Nuts
What is a castle nut?
A castle nut is a hex nut topped with slotted castellations that resemble a castle turret. Those slots align with a hole drilled through the bolt or shaft, allowing a cotter pin to pass through. The pin locks the nut in place and prevents it from loosening under vibration or repeated loads.
Why are castle nuts used instead of standard nuts?
Castle nuts add a positive mechanical lock that ordinary nuts cannot match in high vibration settings. The cotter pin physically prevents rotation, even when torque alone might fail. This makes them dependable for axles, steering joints, and machinery where a loose fastener could cause serious damage or safety risk.
How is a castle nut installed correctly?
The nut is tightened to the specified torque, then turned slightly further if needed to align a slot with the bolt hole. A cotter pin is inserted through the slot and hole, and its legs are bent back to secure it. This sequence keeps the joint both tight and locked.
Where are castle nuts commonly used?
They appear widely in automotive suspension, steering systems, aerospace assemblies, and heavy machinery subject to constant vibration. Their reliable locking action suits wheel bearings, tie rods, and rotating shafts. Engineers choose them wherever a secure, tamper evident fastening is essential for safety and long term performance.
