ThruLok screw bolt fastening system
What ThruLOK Is
The FastenMaster ThruLOK Screw Bolt system is a heavy-duty structural wood-to‐wood fastener from FastenMaster that serves as a screw-in replacement for traditional ½″ through-bolts and carriage bolts used in decking, post, beam, and outdoor framing applications. Instead of drilling large clearance holes, inserting a bolt, and tightening with multiple tools, ThruLOK screws install quickly with a drill/driver and require no pre-drilling in most wood applications.
How the System Works
Unlike a standard screw, the ThruLOK system has a three-part design:
- Hex-head screw with a threaded shaft that pulls materials tight.
- Engineered washer that helps distribute load and resists pull-through.
- LOK-Nut with built-in teeth that grip the wood and can be tightened by hand or drill — no separate wrench/socket required.
This design lets ThruLOK act very much like a through-bolt, but with the ease of installation of a structural screw system.
Key Benefits
- Replaces bolts and carriage bolts: Provides equivalent structural strength with fewer tools and steps.
- No pre-drilling needed: The patented paddle point and thread geometry let it cut into wood easily, saving time on the job site.
- Install with a drill/driver: You don’t need a wrench or ratchet — this speeds installation and cuts labor costs.
- Galvanized & code compliant: Coated finishes meet ACQ corrosion resistance requirements and are suitable for treated lumber and exterior projects.
- Strong structural connection: Works well for posts to rim joists, beams to posts, and other multi-ply timber connections where through-bolts have traditionally been used.
Common Uses
- Connecting deck posts to rim joists or beams.
- Fastening multi-ply beams in outdoor framing.
- Attaching carrying beams to notched posts in deck and pergola builds.
- Any application where a traditional through-bolt would otherwise be required for load-bearing wood-to-wood connection.
Key Specs & Sizes
Lengths: Available in at least 3 common lengths for deck / structural applications:
- 6 ¼″ — typically for a 4×4 post to a 2× joist.
- 7″ — for notched 6×6 bearing beams.
- 8″ — for double 2× to single 4× post / rim-joist connections.
- Drive: Uses a hex head on the screw; the LOK-Nut has wings so you don’t need a wrench to tighten.
- Corrosion / Material: The parts are galvanized, “meets IRC ACQ requirement.”
- Load / Application: Designed for structural connections like posts to beams, multi-ply beams, girder trusses.
Advantages / Why Use ThruLOK
- Speed: Because it’s a self-drilling / self-tapping system, you don’t need to pre-drill, which saves labor.
- Strength: Offers similar (or better) strength than traditional through-bolts, while being easier to install.
- No Wrenches Needed: The LOK-Nut is designed so you can thread it on by hand and tighten with a drill, no socket or ratchet required.
- Corrosion Resistant: Galvanized finish means it’s suitable for treated lumber.
- Versatile Use: Good for common deck / structural scenarios: deck posts, multi-ply beams, notched posts, etc.
- Lifetime Guarantee: FastenMaster backs the ThruLOK system for the life of the project (for structural + corrosion when used / installed correctly).
About this product...
The ThruLok fastening system is used by professional contractors nationwide to meet code and lower costs when attaching deck posts. The 8" Thru Lok has been tested and proven to meet 2012 IRC requirements for joist connections and guardrail post to rim connections. It is a fact that by using the ThruLok system you will save money and time.
DETAILS:
- No pre drilling required
- Installs with an 18-volt cordless drill
- No drill bits or wrenches required
- Galvanized coating meets IRC ACQ corrosion requirement
- Lifetime performance guarantee
- Sold in packs of 24
- Hex Head
SIZES:
- 6-1/4"
- 7"
- 8"
ThruLOK is a code-compliant way to attach deck posts and to secure carrying beams.
- Click HERE for Technical Evaluation Report
