When choosing lag bolts, all-thread options can offer reliable gripping power for wood assemblies, decking, and framing. This guide highlights five solid all-thread lag bolt sets that cover common sizes, finishes, and use-cases. Best for DIYers and professionals needing corrosion resistance, long-lasting hardware, and easy installation. The top picks vary by project size, environment, and whether you need hex heads, eye bolts, or black zinc coatings.
| Product | Size / Thread | Material | Best For | Limitations |
|---|---|---|---|---|
| Prime-Line 9067941 Screw Eye, Lag Thread | 3/8 in x 4-1/2 in | Zinc Plated Steel | Woodworking with eye-joins | Eye end may protrude in tight spaces |
| BNUOK 9 Sets 5/16 x 4 in Hex Lag Screws | 5/16 in x 4 in | 304 Stainless Steel | Outdoor or indoor wooden assemblies | Includes washers; larger kits recommended for heavy loads |
| BNUOK 13 Sets 5/16 x 2 in Hex Lag Screws | 5/16 in x 2 in | 304 Stainless Steel with Black Zinc | Smaller joints or tighter timber connections | Shorter length; less leverage for thick boards |
| EASTPUK 20 Sets 5/16 x 1 in Hex Lag Bolts | 5/16 in x 1 in | 304 Stainless Steel | Decks and light-to-moderate timber joinery | 1 inch length limits deeper joints |
| Fayeploo 3/8 x 1-1/4 in Lag Screws | 3/8 in x 1-1/4 in | 304 Stainless Steel | Medium-duty projects with full thread | Smaller batch size; may require longer for thicker wood |
Prime-Line 9067941 Screw Eye, Lag Thread
Features include a 3/8 inch diameter with a 4-1/2 inch length, combining a closed eye with lag thread for direct wood installation. This product is best for projects requiring an eye bolt connection to wood, such as securing cables or hardware with a robust anchor. Best for DIYers building trellises, outdoor railings, or shelving supports that need an eye point. Limitation: the eye portion adds a protruding feature that may catch in tight spaces or require routing/clearance considerations.
BNUOK 9 Sets 5/16″ x 4″ Hex Lag Screws Bolts
Best for heavy-duty wood connections where corrosion resistance matters. The set uses 304 stainless steel with flat washers and includes a 1/2″ hex driver bit, making it convenient for quick assembly. Suitable for outdoor decks or furniture that may face moisture exposure. Choose this for durability in environments where rust protection is important. Caution: longer screws may require deeper pilot holes to avoid splitting; ensure thickness compatibility with washers.
BNUOK 13 Sets 5/16″ x 2″ Hex Lag Screws
Best for smaller timber joints or projects with thicker frames where longer reach is not required. The set features 304 stainless steel with a black zinc coating for extra corrosion resistance, and includes 13 flat washers and a 1/2″ hex socket driver bit. Better for indoor or enclosed outdoor use. Limitations: shorter length may not provide enough bite in thicker boards; verify joint thickness before purchase.
EASTPUK 20 Sets 5/16″ x 1″ Hex Lag Bolts
Designed for residential and light-industrial timber work, these 1-inch lag bolts are made from 304 stainless steel for improved corrosion resistance. Includes washers and a hex head suitable for quick installation. Best for decks, shelves, or framing where moderate engagement is needed. Caution: the shorter 1-inch length may not be suitable for thicker boards or heavy loads; consider longer options for deeper anchors.
Fayeploo 3/8 x 1-1/4 in Lag Screws
Best for medium-duty wood assemblies where full-thread engagement is beneficial. The set includes 10 screws with flat washers, using 304 stainless steel and black oxide finishing for modest corrosion resistance and a strong hold. Choose this if you need reliable grip across several joints with a consistent thread pattern. Limitation: batch size is smaller; for larger projects, pair with additional fasteners.
Buying Guide
What to consider when selecting all-thread lag bolts:
- Material and finish: Stainless steel (304/18-8) offers corrosion resistance, suitable for outdoors; black zinc adds a style and extra protection for indoor use.
- Length and diameter: Match bolt length to wood thickness and the load you expect; larger diameters provide more shear strength, longer lengths provide deeper engagement.
- Thread type and head style: Hex heads are easier to drive with standard bits; eye bolts add attachment points but can protrude; fully threaded lag screws can maximize grip in wood fibers.
- Included hardware: Sets with washers and driver bits simplify installation and protect the wood surface.
- Application environment: Outdoor decks and furniture require corrosion-resistant finishes; indoor projects may tolerate standard coatings.
FAQ
- What is an all-thread lag bolt?
It is a lag screw with continuous threads along the shaft, designed to pull wood pieces together firmly.
- When should I use a lag bolt with washers?
Washers distribute load and protect wood surfaces, particularly on soft woods or when fastening near edges.
- Are stainless steel lag bolts better for outdoors?
Yes, stainless steel resists rust and corrosion in exposed environments, prolonging joint strength.
- How do I choose the right length?
Measure the combined thickness of the joined materials and aim for at least 1.5 to 2 times the wood thickness for secure fastening.
- Can I use eye lag bolts for all projects?
Eye lag bolts are ideal when you need an anchor point for cables or straps, but they add a protruding end; ensure clearance in crowded installations.