The 7 Best square Head Lag Screws (2023 reviews)

We consider a square head lag screw to be a worthy investment in the long run. We are here to help you choose the right one for your purposes from all the best available products in market today.

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Our Top Picks:

Best Overall: Buy: Makers Bolt square Head Lag Screw READ REVIEW

Best With custom bit: Buy: SPAX square Head Lag Screw READ REVIEW

Best For every project: Buy: National Hardware square Head Lag Screw READ REVIEW

Best For treated lumber: Buy: Jake sales square Head Lag Screw READ REVIEW

Best For routine maintenance: Buy: Jrouth square Head Lag Screw READ REVIEW

Best With Shield: Buy: Qlvily square Head Lag Screw READ REVIEW

Best For metal: Buy: Binifimux square Head Lag Screw READ REVIEW

Best Overall: Makers Bolt square Head Lag Screw

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Makers Bolt has been making good-quality screw for years, thanks to a combination of clever design and high-end materials. These metal wood screws are great for exterior household and industrial applications such as deck building or joining lumber. It is manufactured and finished with makers in mind. The Makers Bolt fasteners are of the highest commercial-grade quality with uniform threads and well-defined heads and points. They're the same quality and will last a long time as well.

These stainless black screws are coated with black oxide proudly applied in the usa to military specifications, giving the screws a sleek look and added corrosion and abrasion resistance. It is great to mount a pull up bar. Durable oxide and dry wax coating provide enhanced protection against peeling, scratches, and corrosion. It is great replacement bolts for security doors if you dont need one-way 4” screws.

• Confident enough to park a nice car under them every day
• Easy to use, fit into ratchet perfectly, appears to be well coated
• Great quality lag screws, highly recommended
• Great quality lag screws with a high quality paint finish

Best With custom bit: SPAX square Head Lag Screw

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The spax square head lag screw's superior materials makes sure that it ages well with use. This is a durable, quality screw ideal for mounting flat surfaces flush without countersinking. It pulls pieces of wood together effortlessly. The profile, large diameter head design provides outstanding clamping force and improved aesthetics. The fit with the custom bit is tight and doesn't slip.

These spax fasteners will work fine for your shutters. It offers excellent bit engagement without requiring a “special” driver bit. Its profile, large diameter head design provides outstanding clamping force and improved aesthetics. They drive in quickly and hold very well without countersinking. These are great for building.

• Outdoor ready with all other spax qualities
• Incredible strength and gripping power combined with a coating suitable for outdoor use
• Great quality and easy to drive with the star driver head
• Good screws that look good with the head exposed

Best For every project: National Hardware square Head Lag Screw

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National Hardware line of screw come in a pretty wide variety of styles, so you can definitely find one that suits your individual preferences and needs. It is built with simplicity in mind. It comes with a design style that is both simple and classic, this piece is usable on both of national hardware's indio and hartley collections. It is great for holding fat pieces of wood together. These are big and chunky. It can be used on a new pergola. It comes in shorter 1-1/2 inch lengths.

• Finished with a black powder coat, for protection from corrosion
• Great product, nice finish on the lag
• Use to install decorative outdoor reinforcement

Best For treated lumber: Jake sales square Head Lag Screw

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It has better compression that forces deep, wide, sharp screw threads. It is an excellent screw for construction applications including, decking, fencing, roofing, framing, timber frame, post & beam etc. It provides twice the torque of phillips or square drive screw heads. It reduces the need for pre-drilling in even hard woods.

The high quality screw threads cut cleanly and easily through tough materials. These have fairly decent grab, but do tent to strip the wood out if you are too aggressive.

• Hour corrosion resistance in both acq and salt spray conditions
• Heat treated steel, triple coated, and acq treated lumber compatible
• New and hot release

Best For routine maintenance: Jrouth square Head Lag Screw

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Jrouth offers a variety of screw for personal choice and yet maintaining quality in all the variants. The black oxide coating is perfect. It includes 5 different most common used sizes. The coating is very uniform and shiny and makes these lag screws really attractive. It is coated with a black oxide. The lags of varying sizes from 1” to 3” appear strong and are oxidized coated to provide corrosion resistance. It is great to securely attach to studs. These bolts are well made and you will keep them for future needs. They come with an amply supply of washers.

• A great set of use-anywhere lag screws
• Stainless steel which is very helpful in this marine, corrosive environment
• New and hot release

Best With Shield: Qlvily square Head Lag Screw

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We know from years of feedback from readers, customers and amazon sellers, what most people want in a convenient and appropriate screw. The qlvily square head lag screw is exactly that - it's a simple screw that hits all the right notes. The length of these lag bolts is perfect to fasten some panels securely to the wood. They all go into the wood easily and tighten up without breaking or stripping out. It has magnetism, which is not as big as iron. The bolt is clearly stainless steel so should not rust and the black coating is well enough applied that it should not peal.

The packaging is a brittle clear plastic bag. It has 10 threads per inch. It is perfect fit and snug as a cork in a wine bottle. These come with flat washers.

• Comes with washers and the size and material checks out
• Sturdy and very pleasant to work with and look at
• Well made lag screws with washers
• Black coating is well applied, bold is super sharp and washers are perfect

Best For metal: Binifimux square Head Lag Screw

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These extremely strong fasteners are usually used to connect heavy wood or other heavy materials that are subjected to high loads. Compared with most ordinary screws, the size of the lag screw is very large. These screws are different from ordinary wood screws, self-drilling screws or metal plate screws. They are a slightly smaller metric size.

These are driven by a wrench and are mainly used for fastening to masonry or wooden frames. It comes with a storage box. These screws are a slightly smaller metric size.

• New and hot release
• One of the new comers and featured product