The Multiquip 51221 Castle Nut is a genuine OEM fastener designed for Whiteman hydraulic power buggy models including the WBH-16, WBH-16E, WBH-16F, WBH-16EF, WBH21EPA, WBH-21EF, and WBH-21EFP series. As a direct Multiquip OEM component, part 51221 meets the original design specification for secure, controlled clamping in its respective assembly. Sourcing the correct castle nut matters — this slotted fastener is engineered to work in conjunction with a cotter pin to lock the nut in position and prevent loosening under load and vibration. Keep a spare on hand to stay ready during routine maintenance or axle service.
Key Features
- Genuine OEM Fastener Grade — Manufactured to Multiquip's original material and thread specification, ensuring the correct torque retention and shear resistance expected of a castle nut in a load-bearing application.
- Slotted Crown for Positive Locking — The castellated profile is designed to accept a cotter pin through the mating shaft, mechanically locking the nut against rotation and preventing loosening caused by vibration or dynamic loading.
- Broad WBH Series Coverage — Fits WBH-16, WBH-16E, WBH-16F, WBH-16EF, WBH21EPA, WBH-21EF, and WBH-21EFP Whiteman hydraulic power buggies.
- Installs as a Direct Drop-In — Matches the original thread pitch and nut dimensions of the factory assembly so no thread chasing or additional hardware modification is needed during installation.
- Safety-Critical Retention Component — Castle nuts are commonly used on wheel spindles and steering linkages; using the correct OEM-spec nut and pairing it with a fresh cotter pin is essential to maintaining safe operation of the buggy.
A castle nut — named for its slotted, crown-like top — is a specialized fastener used in applications where a threaded connection must be secured against rotation. Once torqued to specification, a cotter pin is inserted through the slots and a corresponding hole in the shaft, creating a positive mechanical lock that holds the nut in place even under continuous vibration and cyclic loading. On power buggies, these nuts are typically found at wheel hubs or other rotating assemblies where an ordinary nut could back off over time and create a hazardous condition. A worn, damaged, or missing castle nut compromises the integrity of the entire fastened joint — always replace it with the correct OEM part and install a new cotter pin at the same time.
Part Details
| Part Number | 51221 |
|---|---|
| Brand | Multiquip |
| Part Type | Genuine OEM |
| Description | Castle Nut |
Compatibility & Fitment
| Name | Model |
|---|---|
| Power Buggies | WBH21EPA |
| Power Buggies | WBH-16 |
| Power Buggies | WBH-16E |
| Power Buggies | WBH-16F |
| Power Buggies | WBH-16EF |
| Power Buggies | WBH-21EFP |
| Power Buggies | WBH-21EF |
Verify Before You Order
Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.
Why Buy From DHS Equipment
Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.
Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.
