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5/8-18 Spindle Slotted Jam Nut (Castle Nut)
62FNSJO 5/8-20 Spindle Slotted Jam Nut (Castle Nut)
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5/8-18 Spindle Slotted Jam Nut (Castle Nut)

Part Number: 62FNSJ0
Online Price: $2.95
62FNSJO 5/8-18 Castle Nut – Slotted Jam Nut for High-Security Racing Applications
Availability: In Stock.

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Description

62FNSJO – 5/8-18 Slotted Jam Nut (Castle Nut) – Right-Hand Thread


The 62FNSJO 5/8-18 Slotted Jam Nut, also known as a castle nut, is a safety-critical fastener designed for applications where a nut must be securely locked in place with a cotter pin, R-clip, or safety wire. Its slotted design prevents loosening due to vibration or rotational force—making it an essential component in high-performance and safety-sensitive builds.


Commonly used on spindle axles, wheel hubs, and other rotating or load-bearing assemblies in racing go-karts, lawnmowers, and custom chassis, this nut ensures critical parts stay locked under extreme conditions. The 62FNSJO features 5/8-18 right-hand threads and is supplied uncoated (bare steel), making it ideal for builders who prefer to apply their own finish or plating.


Product Specifications:

  • Thread Size: 5/8"-18 (UNF)
  • Thread Direction: Right-hand
  • Style: Slotted / Castle Nut
  • Finish: Bare steel (no plating)
  • Application: Spindle axles, wheel hubs, chassis components
  • Locking Method: Cotter pin, R-clip, or safety wire (not included)
  • Sold individually


Key Features:

  • Slotted design allows for secure locking with cotter pin
  • Ideal for use in safety tech inspections and racing regulations
  • Used in go-karts, racing mowers, and other small-engine performance builds
  • Compatible with 5/8” diameter threaded shafts
  • Bare finish allows for custom coatings or anti-corrosion treatment


Common Uses:

  • Locking down spindle axles on race mowers or karts
  • Securing wheel hubs or rotating components
  • Safety retention on steering arms, or chassis mounts

FAQ

What is a castle nut used for in racing applications?

A: Castle nuts (slotted jam nuts) are commonly used to secure critical components like spindle axles, steering arms, and wheel hubs. The slots allow a cotter pin or safety wire to pass through the nut and the shaft, preventing it from loosening during use.


What is the thread size and direction?

A: The 62FNSJO castle nut uses a 5/8"-18 UNF right-hand thread, compatible with most standard 5/8" axle and spindle threads.


Is this nut plated or treated for corrosion resistance?

A: No, this nut is sold as bare steel (unplated), allowing builders to apply their own surface treatment, plating, or anti-seize as needed for specific environments.


Can I use this on a go-kart or racing mower?

A: Absolutely. This nut is commonly used in racing go-karts, lawnmowers, and other small-engine vehicles where high vibration and safety are concerns.


Does it come with a cotter pin?

A: No, the cotter pin or safety clip is not included and must be purchased separately.

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