M3–M8 Grade 8.8 Hex Socket Cap Screws Black Oxide Allen Bolts 10PCS

JARBLUE Grade 8.8 Hex Socket Cap Screws – M3, M4, M5, M6 & M8

Upgrade your metalworking, fabrication, or DIY projects with these precision-engineered Grade 8.8 Hex Socket Cap Screws from JARBLUE. Available in sizes M3, M4, M5, M6, and M8, these cylinder-head Allen bolts are built for high-strength fastening applications where reliability matters. The black oxide finish provides a sleek, professional appearance while adding a layer of corrosion resistance for everyday use.

Key Features

• Grade 8.8 Carbon Steel – High tensile strength for demanding mechanical and structural applications
• Black Oxide Finish – Provides a clean, professional look and mild corrosion resistance
• Hex (Allen) Socket Drive – Internal hexagon head for secure torque application and easy installation
• Multiple Sizes in One Pack – Covers M3, M4, M5, M6, and M8 for versatile use
• Cylinder Head Design – Low-profile cap head fits flush in countersunk or recessed applications
• 10 Pieces Included – Great for repairs, builds, and keeping your fastener supply well stocked
• Wide Compatibility – Suitable for machinery, electronics enclosures, woodworking jigs, automotive components, and more

Specifications

What Can You Use These For?

These hex socket cap screws are a workshop staple. Whether you're assembling CNC machines, fixing household furniture, building RC models, securing electronic enclosures, or working on automotive assemblies, the Grade 8.8 rating ensures you have the holding power you need. The internal hexagon drive prevents cam-out and allows torque to be applied in tight, recessed spaces where traditional screwdrivers can't reach.

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Frequently Asked Questions

Q: What sizes are included in this pack of hex socket cap screws?

A: This listing covers M3, M4, M5, M6, and M8 sizes. Each pack contains 10 pieces, and you can select the specific size you need. These metric sizes make them compatible with a wide range of machinery, hardware, and DIY projects.

Q: What does Grade 8.8 mean for these carbon steel Allen bolts?

A: Grade 8.8 is a standard strength classification for metric bolts. It means the bolt has a minimum tensile strength of 800 MPa and a yield strength of at least 640 MPa — making these screws suitable for medium-to-high-load structural and mechanical fastening applications.

Q: What tool do I need to drive these hex socket cap screws?

A: You'll need a standard metric Allen key (hex key) or a hex bit socket set. The drive size corresponds to the screw's metric designation — for example, an M5 cap screw typically requires a 4mm Allen key. Always use the correct size key to avoid stripping the socket.

Q: Is the black oxide finish rust-proof?

A: The black oxide coating offers mild corrosion resistance and is ideal for indoor or low-humidity environments. For outdoor or high-moisture applications, we recommend applying a light machine oil to the screws or opting for stainless steel fasteners instead.

Production & Packaging Notice

To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.