"IMSCREWS 5/16 x 3-1/2 Heavy-Duty Lag Screws - 304 Stainless Steel (5 pcs)

Extreme Reach for Structural Framing
When your project demands deep penetration, these 3.5-inch bolts provide the necessary depth for heavy-duty anchoring. The 5/16 diameter offers professional-grade shear resistance, making them ideal for securing thick timber rails to 4x4 or 6x6 posts in safety-critical outdoor structures.

Vise-Like Clamping Power
Our partially threaded shank features a smooth upper section that pulls the outer board tightly against the support beam. This clamping effect creates a gap-free, rock-solid joint, eliminating the bridging effect common in extra-long full-thread screws for a professional-grade finish.

304 Stainless Weather Protection
Forged from premium 18-8 (304) stainless steel for superior rust resistance. compatible with ACQ pressure-treated lumber. Prevents unsightly rust streaks on high-value cedar, redwood, or premium deck framing even in humid or coastal environments.

FAQ
¡ñ Tools: Fits a standard 1/2 hex socket or wrench.
¡ñ Pre-drilling: Mandatory for this length. Use a 3/16 bit for softwoods or 7/32 bit for hardwoods to prevent timber splitting.
¡ñ Why 3.5 length? Perfect for passing through 1.5 or 2 timber with a massive 1.5 + thread anchor in the base post.

Specs:
- Size: 5/16 x 3-1/2
- Thread: Partially Threaded (Max Clamping)
- Material: 304 Stainless Steel
- Drive: 1/2 Hex Head
- Qty: 5 pcs"

Key Features

• ULTIMATE CLAMPING POWER The engineered partial thread allows the smooth shank to bypass the outer beam, drawing heavy timbers together for a gap-free, rock-solid joint.
• ELITE HOLDING STRENGTH With a 3.5-inch reach and 5/16 oversized diameter, these lag bolts provide superior lateral and withdrawal resistance for high-load brackets.
• 304 EXTERIOR DEFENSE Forged from premium 304 (18-8) stainless steel to prevent rust and staining in cedar, redwood, or ACQ pressure-treated lumber.
• STABLE TORQUE INTERFACE Precision hex head ensures a secure 1/2 socket fit, offering maximum torque transfer for controlled seating in extra-dense hardwoods.
• TECHNICAL SPECIFICATION To prevent splitting and protect the 5/16 shaft, pre-drilling a pilot hole (7/32 for softwoods, 1/4 for hardwoods) is mandatory.

Specifications

• ASIN: B0F21B3NT2
• Internal SKU: IMS0645
• Size: 5/16" x 3-1/2"
• Material: Stainless Steel
• Finish: Stainless Steel
• Head Style: Hex
• Package Quantity: 5