Choosing the right structural bolt can mean the difference between a safe, code-compliant build and costly repairs. This guide examines today’s practical options — from engineered timber through-bolts to budget wall anchors — using hands-on testing, standards research, and consumer feedback to recommend the best choices for common structural tasks.
How we tested and chose
What we tested: real-world installation, corrosion resistance, drive/installation effort, torque and withdrawal strength (where applicable), and compatibility with common building materials (treated lumber, plywood, drywall, masonry).
Sources considered: manufacturer specs and code claims, third-party lab reports, installation guides, expert contractor feedback, and hundreds of user reviews to surface consistent failure modes or praise.
Why it matters: We prioritized fasteners that deliver documented structural performance, ease of installation, and long-term durability. For lighter-duty scenarios we included reliable budget anchors that are appropriate for specific structural-adjacent uses (e.g., holding hardware to hollow walls).
FastenMaster ThruLOK 7in
A code-minded engineered through-bolt replacement for heavy timber connections. The 7" ThruLOK installs fast with a cordless drill, removes the need for pre-drilling, and is ACQ/IBC/IRC code compliant — ideal for post-to-beam and beam-to-beam structural connections.
Overview
FastenMaster ThruLOK 7" is an engineered fastening system designed to replace carriage and through-bolts in many timber framing applications. It’s galvanized for treated-wood use and rated to meet code requirements.
Standout features
- No pre-drilling required for most installs — speeds up framing work.
- Galvanized finish meets ACQ and building code corrosion requirements.
- Designed for heavy connection points: attaching beams, posts, and rim joists.
Analysis
In hands-on installs the 7" ThruLOK showed excellent driving behavior using an 18V drill and standard hex bits; the mechanism draws and clamps material tightly with consistent clamping force. For contractors replacing carriage bolts or through-bolts it reduces labor and eliminates the need to fish hardware through thick members. The main trade-off is cost per fastener versus simple anchors — but for load-bearing connections this system balances speed, code compliance, and long-term durability.
ThruLOK 6-1/4in
A slightly shorter ThruLOK variant optimized for typical post-to-joist and 4x4-to-joist connections. It keeps the same code-compliant coating and install method, offering a solid balance between size and performance for most timber-frame tasks.
Overview
The ThruLOK 6-1/4" variant targets common ledger and post connections where a full 7" depth isn’t needed. It carries the same galvanized, code-compliant finish and installation benefits as the larger ThruLOK.
Standout features
- Code-compliant corrosion protection for treated lumber.
- Engineered clamp and draw action replaces many carriage bolt applications.
- Installs quickly with standard drills — reduces crew time.
Analysis
During bench and field installs the 6-1/4" ThruLOK delivered consistent clamping and matched spec-driven expectations for many residential structural tasks. It’s slightly more economical than the larger size when depth is limited, and it remains our pick for routine post and beam connections where approved by structural plans. Limitations: not a direct substitute where an engineer specifies a specific grade or diameter bolt — always confirm with plans.
Combo Sidewalk Bolts
A 100-piece pack of stainless steel sidewalk/hurricane bolts built for corrosion resistance and frequent reuse. These are ideal for shutter hardware and panel fastening where many fasteners are needed and stainless longevity matters.
Overview
This 100-piece combo pack provides 1/4" stainless truss-head bolts commonly used for shutter installation, panel fastening, and light exterior attachments.
Standout features
- 100 bolts per pack — economical when many fasteners are required.
- Stainless steel construction for excellent corrosion resistance in coastal or wet environments.
- Truss head profile distributes load for thin-panel fastening.
Analysis
For homeowners and installers needing many fasteners (for hurricane panels, shutters, or removable covers), this kit offers strong value: high corrosion resistance, a versatile head profile, and a large count per box. These aren’t engineered structural bolts for primary load paths, but they’re a cost-effective, durable solution for protective panels and repeated installations.
Molly Bolt 50-Pack
A low-cost 50-pack of molly (hollow-wall) anchors designed for secure attachments into drywall and plaster. Best for non-load-bearing fixtures such as light rails, shelving, or mounting hardware where a hollow-wall solution is needed.
Overview
The Prime-Line Molly Bolt 50-pack is a classic hollow-wall fastener. When installed correctly it provides a reliable anchor in drywall and plaster for moderate loads.
Standout features
- Zinc-plated steel construction for basic corrosion resistance.
- Collapsible sleeve expands behind the wall for secure hold.
- Large pack size keeps unit cost low for multiple installs.
Analysis
These molly bolts are a pragmatic budget choice when you need to hang fixtures on hollow walls and cannot reach a stud. They are not intended for primary structural loads, but for many interior mounting tasks they deliver predictable performance at a very low price. For heavy structural connections, use engineered through-bolts or structural connectors instead.
Quick comparison — key differences
- FastenMaster ThruLOK 7" (Premium Choice): Engineered replacement for through-bolts, code-compliant, great for heavy timber connections; highest price but designed for structural use.
- ThruLOK 6-1/4" (Editors Choice): Same system in a shorter length — excellent for most post-to-joist connections, slightly more economical and our top practical pick.
- Combo Sidewalk Bolts (Best Value): Large pack of 304 stainless bolts for exterior paneling and shutter hardware; excellent corrosion resistance and per-fastener value.
- Molly Bolt 50-Pack (Best Budget): Inexpensive hollow-wall anchor for light-to-moderate interior loads; not for primary structural use.
Best overall for structural timber connections: ThruLOK 6-1/4" (Editors Choice) for its balance of size, performance, and cost. For heavy or deeper connections choose the 7" ThruLOK.
Alternatives that excel in specific areas:
- Corrosion-heavy coastal projects: choose stainless-fastener packs (Combo Sidewalk Bolts) for paneling and non-structural attachments.
- Tight budgets or hollow-wall needs: Molly Bolt 50-pack is appropriate for light fixtures and hardware.
Final recommendation
If you’re specifying fasteners for structural timber connections, the engineered ThruLOK systems are the best option from today’s picks — they reduce installation time, meet corrosion code requirements for treated lumber, and are designed for load-bearing connections when used per manufacturer and code guidance. For routine post-to-joist and ledger connections the ThruLOK 6-1/4" is our go-to recommendation; choose the 7" variant when you need greater embedment.
For non-primary-structure needs — shutters, removable panels, or many small exterior attachments — the stainless combo bolts offer the best blend of corrosion resistance and value. And for interior, hollow-wall fixtures on a tight budget, molly bolts remain the practical solution.
These recommendations are based on hands-on installation testing, manufacturer specifications, code and corrosion considerations, and broad user feedback. Always verify your fastener selection against project drawings and local building codes, and consult a structural engineer for load-critical connections.