HeadLOK Structural Wood Screw

HeadLOK is a heavy duty structural wood screw that is ideal for many wood applications including deck framing, stair stringers, attaching rigid foam (SIPs), fences, kitchen cabinets and more. The HeadLOK flat head fastener requires no predrilling and offers higher design shear than 3/8" lag screws. The SpiderDrive™ System contains 8 points of contact, maximizing bit fit and reducing stripping. HeadLOK zips right in and creates a great finished look.

  • 3/8” lag screw replacement
  • No predrilling
  • Flat head provides great finished look
  • Sharp gimlet point for fast installation into wood and OSB
  • Aggressive thread for holding and withdrawal strength
  • Free SpiderDrive™ bit in every package

For HeadLOK technical information and drawings, see the Technical Docs section below. For technical documentation of all our structural wood screws, see our Technical Resources page.


HeadLOK Flathead Structural Wood Screw

Learn how our HeadLOK Flathead Structural Wood Screw is ideal for fastening a variety of wood applications.

  • Sku Selections
  • Installation
  • Technical Docs
  • Purchase FM Products
HeadLOK SKU Selection Guide    
 2 7/8"   12 pc clamshell   FMHLGM278-12
50 pc box FMHLGM278-50
500 pc bucket FMHLGM278-500
 4 1/2"   12 pc clamshell   FMHLGM412-12
50 pc box FMHLGM412-50
250 pc bucket FMHLGM412-250
 6"   12 pc clamshell   FMHLGM006-12
50 pc box FMHLGM006-50
250 pc bucket FMHLGM006-250
1 5/8" 500 pc bucket FMHLGM158-500
3 3/4" 250 pc bucket FMHLGM334-250
5" 250 pc bucket FMHLGM005-250
5 1/2" 250 pc bucket FMHLGM512-250
6 1/2" 250 pc bucket FMHLGM612-250
7" 250 pc bucket FMHLGM007-250
7 1/2" 250 pc bucket FMHLGM712-250
8" 250 pc bucket FMHLGM008-250
8 1/2" 250 pc bucket FMHLGM812-250
9" 250 pc bucket FMHLGM009-250
9 1/2" 250 pc bucket FMHLGM912-250
10" 250 pc bucket FMHLGM010-250
11" 250 pc bucket FMHLGM011-250
12" 250 pc bucket FMHLGM012-250
13" 250 pc bucket FMHLGM013-250
14" 250 pc bucket FMHLGM014-250
15" 250 pc bucket FMHLGM015-250
16" 250 pc bucket FMHLGM016-250
18" 250 pc bucket FMHLGM018-250
HeadLOK Carded Bit (2 pk) FMSPIDER3-2PK

HeadLOK should be installed using a ½" high torque drill (18V Cordless or higher), drive the HeadLOK head flush to the surface. No predrilling required when proper end and edge distances are maintained.

HeadLOK should be installed using an impact driver or high torque 1/2" variable speed drill (minimum 18V if cordless). Choose the proper length fastener so that the threads fully engage the main member (second piece). Bring the washer head flush to wood surface.

ICC-ES Report, ESR 1078

The ICC-ES Evaluation Report demonstrates to the installer and code official that our LOK fasteners comply with the most current building codes. This report also provides the engineer with critical values needed to design safe installations. Reports from ICC-ES are the most recognized reports used by code officials across the U.S. This document can be shared with code officials, engineers, architects and specifiers who may have questions regarding proper use or code compliance of LOK fasteners.

Technical Evaluation Reports (TERs)

TERs qualify for building official approval and are developed from test reports that comply with IBC Section 104.11.1

HeadLOK Rigid Foam to Wood Framing (TER 1009-01)

This file contains Technical Evaluation Report (TER) for attaching HeadLOK to wood framing through exterior rigid foam sheathing.

HeadLOK Top Plate and Bottom Plate to Stud (TER 1201-01)

This file contains Technical Evaluation Report (TER) for attaching HeadLOK top and bottom plates to studs.

DWG Drawings

For use in CAD software

Warranty Information

HeadLOK Guarantee of Performance

This file contains information regarding HeadLOK Wood Screw guarantee of performance

Catalog Pages

Product specific pages from our FastenMaster catalog.

Code Compliance Reports

Code Compliance Reports by State / Province

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