Flat Washer Head Partially Threaded Structural Wood Screws, 4.0
  • Code Approval
  • ICC , ETA
  • Connection Type
  • Wood/Wood
  • Applications
  • Timber Framing , Log Home Building , Mass & Heavy Timber Construction
  • Manufacturer
  • SWG

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Flat Washer Head

Partially Threaded

Shank Cutter

Reamer Tip

Product Description

Product Description

The ASSY FWH 4.0 are partially threaded high performances structural fasteners. They are ICC-ESR [3179] approved fasteners, designed to pull connection elements tightly together.

They are two-in-one engineered screw that combines the pulling power of a washer-head screw with the clean finish of a countersunk head screw. Their design offers a precise setting without the need for pre-drilling [may be recommended for long models]. Their blue passivated zinc coating makes them adequate for use in low corrosive environment, such as dry service condition. They participate in LEED BD+C 2.0 certification [MRc 4.1 & 4.2, 2 points possible] thanks to the percentage of post-consumer recycled steel used to manufacture them.



Diameters 5/16″ (8 mm)
Lengths4″ (100 mm)  to  15-3/4” (400 mm)
  • Partially threaded structural fasteners 4.0
  • Installed with RW Bits
  • Flat washer head for a clean architectural finish
  • Ideal for wood-to-wood connections
  • Blue passivated zinc coating
  • Reamer tip providing the fastest fastener wood bite & installation
  • Equipped with a shank cutter reducing the installation torque needed
  • LEED certification letter available upon request




SpecificationASSY F.W.H.Thread LengthDrive BitPackaging Qty.
# ItemMaterialHead
[4] FWH08080Hardened SteelFlat Washer Head5/16" x 3 1/8"8 x 0802"50RW 4050
[4] FWH08100Hardened SteelFlat Washer Head5/16" x 4"8 x 1003 1/8"80RW 4050
[4] FWH08160Hardened SteelFlat Washer Head5/16" x 6 1/4"8 x 1603 1/8"80RW 4050
[4] FWH08200Hardened SteelFlat Washer Head5/16" x 7 7/8"8 x 2003 1/8"80RW 4050
[4] FWH08240Hardened SteelFlat Washer Head5/16" x 9 1/2"8 x 2404"100RW 4050
[4] FWH08300Hardened SteelFlat Washer Head5/16" x 11 7/8"8 x 3004"100RW 4050
[4] FWH08360Hardened SteelFlat Washer Head5/16" x 14 1/4"8 x 3604"100RW 4050
[4] FWH08400Hardened SteelFlat Washer Head5/16" x 15 3/4"8 x 4004"100RW 4050
Design Guides

Design Guides

Structural Screw Catalog

A catalog with all information on our ICC & CCMC code-approved fasteners, including dimensions, references & design properties.

Code Approvals

Code Approvals

ICC Code Approval ESR-3179 for Partially Threaded Fasteners - 2022 Edition (October)

ISO 50001 Certification for ASSY Fasteners

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