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Strong-Drive® SWD Double-Threaded™ Screw 

Introducing the new Strong-Drive SWD Double-Threaded screw. This innovative fastener designed for stealth, strength and speed is ideal for securing two wood members together on exterior or interior structural jobs. Available in an assortment of lengths, the SWD™ screw can be used in a variety of applications such as knee bracing, fastening beam to post, beam to joist, or guardrail to post with ease. The screw features a chisel point for reduced splitting, a smooth, unthreaded mid-shank to secure wood members tight, and a compact head for low visibility. Code listed for structural applications, the SWD has a black, exterior-grade, double-barrier coating for corrosion resistance.

Key Features

  • Professional grade — engineered for strength, versatility and reliability  
  • Double-thread design and smooth mid-shank pull members together securely
  • Black, exterior-grade, double-barrier coating for corrosion resistance  
  • Chisel point provides easy driving for angled installation and reduced splitting
  • Compact cylinder head design for low visibility, concealed installations
  • 6-lobe driver bit for secure driving
  • Code listed and load rated for structural applications

Applications

  • Fasten a variety of connections with ease, such as knee bracing, beam to post, beam to joist, purlin to truss, guardrail to post, roof to wall, and post cap connections replacement, along with post-frame configuration and multi-ply assembly.

Product Includes

  • 1 6-lobe driver bit: 
    • T30 for 2 1/2", 3 1/2", 6 1/4" sizes
    • T40 for 8 1/2", 10 3/4" sizes

Finish

  • Black, exterior-grade, double-barrier coating for medium-level corrosion resistance

Related Literature

Double-threaded. Low profile. Code listed.
S-F-SWD24
A sales flier providing features and benefits for the Strong-Drive® SWD Double-Threaded™ screw lineup.
Flier
New Strong-Drive® SWD DOUBLE-THREADED™ screw for Exterior Structural Wood Connections
F-F-SWD24
A flier providing product descriptions, features, benefits and load tables for the Strong-Drive® SWD Double-Threaded™ screw lineup.
Flier
Strong-Drive® SWD Double-Threaded™ Screw for Joist-to-Beam Connections
L-F-SWDJSTBM24
This letter provides supplemental information for using the Strong-Drive SWD Double-Threaded screws in joist-to-beam connections.
Engineering Letter
Strong-Drive® SWD Double-Threaded™ Screw for Post-to-Beam Knee/ Diagonal Bracing Connections
L-F-SWDKNEE24
This letter provides supplemental information for using the SWD screw in knee-bracing in-line with post and beam and 2x side lap diagonal bracing connections.
Engineering Letter
Strong-Drive® SWD Double-Threaded™ Screw for Purlin-to-Truss/Rafter Connections
L-F-SWDPLTRS24
This letter provides supplemental information for using the SWD screw in purlin-to-truss/rafter connections.
Engineering Letter
Strong-Drive® SWD Double-Threaded™ Screw for Truss/Rafter-to-Top Plate Connections
L-F-SWDRFWL24
This letter provides supplemental information for using the SWD screw in truss/rafter-to-top plate connections.
Engineering Letter
Strong-Drive® SWD Double-Threaded™ Screw – Beam-to-Post Connections
L-F-SWDBTPTOP24
This letter provides supplemental information for using the Strong-Drive SWD Double-Threaded screws in beam-to-post connections.
Engineering Letter
Strong-Drive® SWD Double-Threaded™ Screw – Beam-to-Post Connections
L-F-SWDBTPBOT24
This letter provides supplemental information for using the Strong-Drive SWD Double-Threaded screws in beam-to-post connections.
Engineering Letter
Strong-Drive® SWD Double-Threaded™ Screw – Wood Railing Assemblies
L-F-SWDRAIL24
This letter provides supplemental information for using the SWD screw in wood railing assemblies.
Engineering Letter

Product Information Table

Fastener Production Information and Stuff & Things
New products
Model No. Coating/Material Length (in.) Head Diameter (in.) Shank Diameter (in.) Drive Type Head Type Shank Type Thread Type Thread Length (in.) Point Type Color Packaging Qty.
SWD18212DBB-R50 Double-Barrier Coating 2 1/2 0.315 0.180 T30 6-Lobe Cylinder Head Unthreaded Mid-Shank Double Thread 1 1/8 Screw Chisel Point Black 50
SWD18312DBB-R50 Double-Barrier Coating 3 1/2 0.315 0.180 T30 6-Lobe Cylinder Head Unthreaded Mid-Shank Double Thread 1 5/8 Screw Chisel Point Black 50
SWD18614DBB Double-Barrier Coating 6 1/4 0.315 0.180 T30 6-Lobe Cylinder Head Unthreaded Mid-Shank Double Thread 2 1/2 Screw Chisel Point Black 500
SWD18614DBB-R50 Double-Barrier Coating 6 1/4 0.315 0.180 T30 6-Lobe Cylinder Head Unthreaded Mid-Shank Double Thread 2 1/2 Screw Chisel Point Black 50
SWD221034DBB-R30 Double-Barrier Coating 10 3/4 0.394 0.235 T40 6-Lobe Cylinder Head Unthreaded Mid-Shank Double Thread 4 1/4 Screw Chisel Point Black 30
SWD22812DBB-R30 Double-Barrier Coating 8 1/2 0.394 0.235 T40 6-Lobe Cylinder Head Unthreaded Mid-Shank Double Thread 3 3/4 Screw Chisel Point Black 30

Load Tables

Strong-Drive SWD Double-Threaded Screw — Allowable Shear Loads — Douglas Fir-Larch, Southern Pine, Spruce-Pine-Fir and Hem-Fir Lumber

Model Thread Length (in.) DFL/SP Allowable Shear Loads (lb.) SPF/HF Allowable Shear Loads (lb.)
Wood Side Member Thickness (in.) Wood Side Member Thickness (in.)
3/4 1 1/2 3 1/2 5 1/2 7 1/2 3/4 1 1/2 3 1/2 5 1/2 7 1/2
SWD18212DBB 1 1/8 134 156 — — — 109 103 — — —
SWD18312DBB 1 5/8 134 220 — — — 109 159 — — —
SWD18614DBB 2 1/2 134 220 325 — — 109 159 225 — —
SWD22812DBB 3 3/4 163 220 325 450 — 112 155 225 290 —
SWD221034DBB 4 1/4 163 220 325 430 300 112 155 225 330 275
  1. Allowable shear loads are shown at a CD = 1.0. Loads may be increased for load duration per the building code up to a CD = 1.6. Tabulated values shall be multiplied by all applicable adjustment factors from the NDS as referenced in the IBC or IRC.
    2. For in-service moisture content greater than 19%, use CM=0.70 for DFL/SP and CM=0.58 for SPF/HF.
  2. Screws shall be installed straight into the side grain of the wood main member with the screw axis at a 90° angle to the wood fibers.
  3. Minimum main member thickness shall be equal to the screw length minus the side member thickness.

Strong-Drive SWD Double-Threaded Screw — Allowable Withdrawal Loads — Douglas Fir-Larch, Southern Pine, Spruce-Pine-Fir and Hem-Fir Lumber

Model Fastener Length (in.) Thread Length (in.) Reference Withdrawal Design Value, W (lb/in.) Max Reference Withdrawal Design Value, WMAX (lb.)
DFL/SP SPF/HF DFL/SP SPF/HF
SWD18212DBB 2 1/2 1 1/8 148 117 165 130
SWD18312DBB 3 1/2 1 5/8 148 117 240 190
SWD18614DBB 6 1/4 2 1/2 190 178 475 445
SWD22812DBB 8 1/2 3 3/4 194 194 695 695
SWD221034DBB 10 3/4 4 1/4 194 194 695 695
  1. Tabulated reference withdrawal design values are in pounds per inch of the thread penetration into the main member.
  2. Tabulated max reference withdrawal design values are in pounds where the entire thread length shall penetrate into the main member.
  3. Tabulated reference withdrawal design values are shown at a CD = 1.0. Loads may be increased for load duration per the building code up to a CD = 1.6. Tabulated values shall be multiplied by all applicable adjustment factors from the NDS as referenced in the IBC or IRC. For in-service moisture content greater than 19%, use CM=0.70 for SPF/HF and CM=0.56 for DFL/SP.
  4. Screws shall be installed straight into the side grain of the wood main member with the screw axis at a 90° angle to the wood fibers.
  5. End-grain factor of 0.65 shall be applied when installed into the end grain of member.

Strong-Drive SWD Double-Threaded Screw — Allowable Pull-Through Loads — Douglas Fir-Larch, Southern Pine, Spruce-Pine-Fir and Hem-Fir Lumber

Model Fastener Length (in.) Thread Length (in.) Max Reference Pull-Through Design Value, (lb.)
2x Side Member 4x Side Member 6x Side Member
DFL/SP SPF/HF DFL/SP SPF/HF DFL/SP SPF/HF
SWD18212DBB 2 1/2 1 1/8 175 175 — — — —
SWD18312DBB 3 1/2 1 5/8 175 175 — — — —
SWD18614DBB 6 1/4 2 1/2 175 175 540 — — —
SWD22812DBB 8 1/2 3 3/4 260 260 590 — — —
SWD221034DBB 10 3/4 4 1/4 260 260 590 — 695 695
  1. Tabulated maximum reference design values are in pounds into the side member.
  2. Tabulated maximum reference pull-through design values are shown at a CD = 1.0. Loads may be increased for load duration per the building code up to a CD = 1.6. Tabulated values shall be multiplied by all applicable adjustment factors from the NDS as referenced in the IBC or IRC. For in-service moisture content greater than 19%, use CM=0.70 for SPF/HF and CM=0.56 for DFL/SP.
  3. Screws shall be installed straight into the side grain of the wood main member with the screw axis at a 90° angle to the wood fibers.

SWD Doubled-Threaded Screw Spacing Requirements

CONDITION DIRECTION OF LOAD TO GRAIN ID MINIMUM DISTANCE OR SPACING (in.)
SWD18 SWD22
Edge Distance Perpendicular ① 1 1 1/4
Parallel ① 1 3/4 1 3/4
End Distance Perpendicular ② 4 5
Parallel ② 4 5
Spacing Between Fasteners in a Row Perpendicular ③ 4 5
Parallel ④ 4 5
Spacing Between Rows of Fasteners Perpendicular ⑤ 1 1/2 1 3/4
Parallel ⑥ 1 1/2 1 3/4
Spacing Between Staggered Rows Perpendicular or Parallel ⑦ 7/8 7/8

Note: For axial loading, use the following dimensions: For SWD18, end distance = 2 1/2", edge distance = 1", spacing parallel to grain = 1 3/4", spacing perpendicular to grain = 1". For SWD22, end distance = 3", edge distance = 1 1/4", spacing parallel to grain = 2", spacing perpendicular to grain = 1 1/4".
SWD Double-Threaded Screw Spacing Requirements
SWD Double-Threaded Screw Spacing Requirements

Code Reports & Compliance

Drawings

PDF DWG DXF RFA IFC SAT

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