Bulk 5/16"-18 Grade 8 Hex Cap Screws (Zinc Yellow CR+6 Bake, UNC)

Rugged Fasteners for Industrial & Automotive Applications

Enhance the strength and reliability of your assemblies with our 5/16"-18 Grade 8 Hex Cap Screws, treated with a zinc-yellow CR+6 bake for excellent corrosion resistance. Featuring coarse-thread (UNC) design, these screws deliver dependable clamping power, making them ideal for machinery, construction, automotive, and other demanding applications.

Note – PT = Partial Thread

Key Features

• Diameter: 5/16 inch
• Thread Size: 5/16"-18 – UNC (Coarse) Thread
• Length Options: Offered in various lengths to meet different project requirements
• Thread Length: May be fully or partially threaded depending on the total screw length
• Wrench Size (Across Flats): 1/2 inch (standard hex head)
• Material & Finish: Grade 8 alloy steel with zinc-yellow CR+6 bake
• Type: Hex Cap Screw
• System of Measurement: Inch (Imperial / US)
• Specifications: Conforms to ASTM B18.2.1
• Matching Nuts & Washers: 5/16"-18 Nuts & Washers Available Here

Bulk Ordering Advantages

When you purchase these Grade 8 hex cap screws in bulk, you reduce your per-piece costs and secure a consistent supply of high-quality fasteners. This is particularly beneficial for high-volume operations such as industrial manufacturing, automotive repair shops, and construction sites.

Material Properties

• Grade 8 Strength: Designed to handle elevated torque and load requirements.
• Corrosion Resistance: Zinc-yellow CR+6 plating defends against rust and wear.
• Coarse Thread Efficiency: UNC threading ensures a secure grip in heavy-duty applications.

Ideal Applications

• Automotive & Engine Assembly
• Industrial Machinery & Equipment
• Construction & Structural Reinforcement
• Agricultural & Off-Road Machinery
• Maintenance, Repair & Overhaul (MRO)

Why Monster Bolts?

Since 2012, Monster Bolts has been a trusted source for industrial-grade fasteners, offering:

• Reliable Quality: Each fastener meets strict ASTM standards for consistent performance.
• Competitive Bulk Pricing: Lower your total project costs with volume discounts.
• Wide Inventory & Fast Shipping: Keep projects on schedule with quick order fulfillment.
• Expert Support: Our knowledgeable staff can help with product selection and technical inquiries.

Installation Tips

• Choose the correct wrench or impact socket to avoid damaging the screw head or threads.
• Clean and lubricate threads before assembly for accurate torque and secure fastening.
• Pair with Grade 8 nuts and washers for optimal joint integrity and load distribution.

Note: Nuts and washers are sold separately.

Order in Bulk & Save

Equip your operation with 5/16"-18 Grade 8 Hex Cap Screws for dependable performance across challenging applications. Buy in bulk and benefit from cost savings, speedy shipping, and top-notch customer support—hallmarks of Monster Bolts.

✔️ Trusted by professionals across industrial, automotive, and construction sectors

✔️ Zinc-yellow CR+6 finish ensures robust corrosion protection

✔️ Conforms to ASTM B18.2.1 standards for verified reliability