Multiquip 21781-001 HFS Nut 3/8"-16

The Multiquip 21781-001 is a genuine OEM HFS Nut 3/8"-16 designed for a wide range of Multiquip and Whiteman equipment, including light towers, ride-on trowels, walk-behind trowels, masonry saws, roller screeds, and trash pumps. As a factory-sourced fastener, it meets the exact thread specification and material grade required for secure, long-term assembly across multiple machine families. Verify your model against the fitment list below to confirm compatibility before ordering.

Key Features

• Genuine OEM Fastener Grade — Manufactured to the exact thread class and material hardness specified by Multiquip, ensuring full engagement and correct clamping force at every installation point.
• 3/8"-16 Thread Specification — Standard UNC thread pitch threads directly onto existing studs and bolts without chasing or re-tapping, maintaining structural integrity across assemblies.
• Broad Cross-Family Fitment — Compatible with LT12, LT6K, and MLT25DCA light tower series; HHNG4 and HHNG5 mechanical ride-on trowels; PRX hybrid power floats; WRS5200 and WRSPUDF roller screeds; CA and CA Series walk-behind trowels; MS18 and MS20/MS30 masonry saws; and the MQ62TK trash pump.
• Secure Torque Retention — Proper fastener grade and thread form prevent loosening under vibration loads common to compaction, screeding, and pump applications, keeping critical joints tight through extended operation.
• Direct OEM Replacement — Part number 21781-001 cross-references directly to Multiquip's parts system, so you can order with confidence that this nut matches the original hardware your machine left the factory with.

A hex flange serrated (HFS) nut combines a standard hex nut with an integrated serrated flange that bites into the mating surface when torqued, acting as a built-in lock washer. This design resists loosening caused by vibration — a critical property on equipment like trowels, screeds, and light towers that generate continuous operational vibration. When an HFS nut strips, corrodes, or goes missing, the joint it secures can work loose, leading to misalignment, accelerated wear on surrounding components, or structural failure of the fastened assembly.

For fitment questions or help confirming compatibility with your specific unit, contact the DHS Equipment parts team directly.

Part Details

Compatibility & Fitment

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.