Multiquip 22228 HHF 3/8-16X1" Grade 8 Screw

The Multiquip 22228 is a genuine OEM HHF 3/8-16X1" Grade 8 Screw designed for Whiteman ride-on power trowel models including the STX55Y6, STX6H, HTX6H, HTX44K4, HTX44K5, HTXG6DF, HHXG5, HHXD5, HHXD5-ES, HHXDF4-DF5, and STXD6i. As a direct OEM replacement, this screw meets Multiquip's original specifications for strength and thread engagement, ensuring a secure connection in the assembly positions where it was originally installed. Sourced directly from Multiquip, part 22228 is the correct hardware choice when servicing or rebuilding these professional-grade finishing machines. DHS Equipment stocks genuine Multiquip OEM parts to keep your trowel turning with the right components.

Key Features

• Grade 8 High-Strength Hardware — Rated to withstand the elevated tensile and shear loads found in ride-on trowel assemblies, where vibration and torque demand superior fastener strength over standard hardware.
• Correct Thread Specification — 3/8-16 UNC coarse thread matches the original tapped holes and mating fasteners on these machines, allowing the screw to seat and torque properly without rework.
• Genuine OEM Part — Manufactured to Multiquip's original design standards, so dimensions, thread form, and material grade align exactly with the hardware used during factory assembly.
• Broad Ride-On Trowel Coverage — Confirmed fitment across the STX, HTX, and HHX series, including STX55Y6, STX6H, HTX6H, HTX44K4, HTX44K5, HTXG6DF, HHXG5, HHXD5, HHXD5-ES, HHXDF4-DF5, and STXD6i models.
• Structural Integrity Where It Counts — Using the correct grade fastener in load-bearing and vibration-exposed joints prevents fastener fatigue, joint loosening, and potential damage to surrounding components during operation.
• Safety-Critical Fastener Compliance — Substituting lower-grade hardware in structural trowel joints can compromise operator safety; using the OEM-specified Grade 8 screw maintains the integrity of the assembly as designed.

A hex head flange screw combines the clamping function of a standard hex head bolt with an integrated flange that acts as a built-in washer, distributing clamping load across a wider bearing surface without requiring a separate washer. The Grade 8 designation indicates a high-strength alloy steel fastener with a minimum proof load and tensile strength significantly above that of common Grade 5 or Grade 2 hardware, making it appropriate for dynamically loaded joints subject to vibration — exactly the conditions present in an operating ride-on power trowel. When a fastener of this type fails or is replaced with an incorrect grade, joint clamping force drops, components can shift under load, and damage to the trowel's structure or drive system may follow.

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.