"IMSCREWS 3/8 x 4 Heavy-Duty Lag Screws - 304 Stainless Steel (10 pcs)

Extreme Reach for Structural Timber Joints
When your project demands deep penetration and unyielding holding power, these 3/8 x 4 Lag Bolts deliver industrial performance. Perfect for securing landscape timbers, mounting heavy gate posts, or joining structural beams. The 4-inch length provides elite-level stability for thick, load-bearing wood members.

Vise-Like Clamping Power
Our partially threaded shank allows the screw to spin freely in the outer board while the deep threads bite into the support beam. This draws the components together into a gap-free joint, eliminating the bridging effect where boards remain loose—a common failure in extra-long full-thread screws.

304 Stainless Exterior Defense
Forged from premium 18-8 (304) Stainless Steel for ultimate weather resistance. compatible with ACQ pressure-treated lumber, preventing chemical corrosion and ensuring no unsightly rust streaks will ruin your cedar, redwood, or structural deck framing.

Technical FAQ
¡ñ Tools Required: Fits a standard 9/16 hex socket or wrench.
¡ñ Pre-drilling: Mandatory for this diameter and depth. Use a 1/4 bit for softwoods or 9/32 bit for hardwoods to prevent splitting.
¡ñ Why 4 length? Optimized for passing through 2 or 3 thick timber with a strong 1 to 2 thread anchor in the base post.
¡ñ Resilience: Rated for marine, coastal, and high-humidity environments.

Specifications:
- Size: 3/8 x 4
- Thread: Partially Threaded (Max Clamping)
- Material: 304 Stainless Steel (18-8)
- Drive: 9/16 Hex Head
- Qty: 10 pcs"

Key Features

• ELITE CLAMPING POWER The partially threaded design ensures the smooth shank passes through the outer member, pulling heavy timber pieces together with immense force for a gap-free joint.
• INDUSTRIAL STRUCTURAL HOLD The robust 3/8-inch diameter and 4-inch length provide elite shear resistance for heavy-duty framing, 4x4/6x6 posts, and deck main beams.
• 304 STAINLESS DEFENSE Forged from premium 304 (18-8) stainless steel to prevent oxidation deep within wood joints. Chemically compatible with ACQ pressure-treated lumber.
• POWER TOOL OPTIMIZED Features an oversized hex head built for 9/16 power sockets. Designed to handle the extreme torque required for deep 4-inch structural penetrations.
• STRUCTURAL GUIDELINE To ensure joint integrity and prevent timber splitting, pre-drilling a pilot hole (1/4 for softwoods, 9/32 for hardwoods) is mandatory for this massive 3/8 bolt.

Specifications

• ASIN: B0F21BQWCH
• Internal SKU: IMS0680
• Size: 3/8" x 4"
• Material: Stainless Steel
• Finish: Stainless Steel
• Head Style: Hex
• Package Quantity: 10