Lag Screws 6 in #14 x 6 Structural Wood Screws - Heavy Duty Rust

In this review the focus is on a pack of 100 structural lag screws designed for heavy woodworking and outdoor projects; the bottom line is that these screws deliver reliable holding power and corrosion resistance for timber framing, decks and log construction. The reviewer found the biggest reason to buy is the combination of a heat treated steel core and a proven double anti-corrosion coating that passed long salt spray exposure, giving confidence for exterior work. Use of a T30 star drive and a modified truss washer head also simplifies installation and results in neat, flush fastening.

Key Features

• Dimensions & Strength: Six inch length and 0.25 in thread diameter provide deep embedment and strong shear capacity for heavy timber connections.
• Anti-corrosion Coating: Double coatings that passed a 1000 hour salt spray test greatly reduce the risk of rust for outdoor and coastal applications.
• Knurl Thread & Self-tapping: The knurled shank and type 17 notched point reduce torque and let the screw bite into wood with less splitting and fewer pilot holes.
• Modified Truss Washer Head: The washer-style head gives a flush, finished look while spreading load over the surface to prevent pull-through.
• Star Drive with Bit: T30 star drive compatibility reduces cam-out and slips during high-torque installation, improving speed and control.
• Heat Treated Steel: The heat treated construction provides durability and consistency for structural use under load.

Who It's For

These lag screws are aimed at contractors, deck builders and serious DIYers working with large timbers, beams and outdoor structures where long-term corrosion resistance and high holding power matter. They suit projects such as deck building, laminated beams, pole barns and log construction where 6 in length and a robust head are appropriate.

Those who need smaller fasteners, non-structural trim screws, or stainless steel fasteners for extreme marine environments should consider alternative sizes or materials; likewise, if frequent disassembly is expected, a different fastening strategy may be preferable.

Pros & Cons

Pros

• Well-made, heat treated steel gives dependable strength for heavy duty connections.
• Double anti-corrosion coatings and 1000 hour salt spray resistance increase lifespan outdoors.
• Knurled shank and type 17 point make self-tapping installation faster and reduce the need for pilot holes.
• T30 star drive and washer head provide good grip and a neat finished appearance.

Cons

• Some users report mixed ease of use when starting the screw; occasional difficulty with initial engagement can occur without a good starter bit or pilot hole.
• Black coated finish, while rust resistant, is not the same as stainless for the most corrosive marine applications.

Specifications

Length	6 in
Thread Diameter	0.25 in
Head Diameter	0.55 in
Drive Type	T30 star drive
Point Type	Type 17 notched extra sharp point (self-tapping)
Material	Heat treated steel
Coating	Double anti-corrosion coating, passed 1000 hour salt spray test

Our Verdict

For anyone building decks, timber frames or heavy outdoor structures, these 6 in structural lag screws offer strong holding power and proven rust protection at a reasonable pack quantity, making them a practical choice for long-lasting projects. They are good value for contractors and serious DIYers who need durable fasteners designed for structural use.

Frequently Asked Questions

Do these screws require a pilot hole?
They feature a type 17 notched point and knurled shank that reduce the need for pilot holes in many soft and dimensional woods, though a starter hole can help with precise alignment in hardwoods.

What bit is needed?
Use a T30 star bit for reliable engagement with the star drive head; a quality bit reduces slipping and screw stripping.

Are these suitable for coastal use?
The double coating passed a 1000 hour salt spray test which improves corrosion resistance, but they are not stainless steel, so evaluate exposure severity for extreme marine locations.