M8 x 40mm Carriage Bolts Grade 8.8 Steel with Nuts and Washers — 64 - Set - HomeDIYer
Zum Zoomen über das Bild scrollen Klicke zum Zoomen auf das Bild
M8 x 40mm Carriage Bolts Grade 8.8 Steel with Nuts and Washers — 64 - Set - HomeDIYer

M8 x 40mm Carriage Bolts Grade 8.8 Steel with Nuts and Washers — 64-Set

HomeDIYer
Keine Bewertungen

By HomeDIYer®

Preis:
$81.34 USD
Lagerbestand:
Verfügbar (500 Stück), versandbereit

Payment & Security

Amazon American Express Apple Pay Bancontact Diners Club Discover Google Pay iDEAL Wero Mastercard PayPal Shop Pay USDC Visa

Deine Zahlungsinformationen werden sicher verarbeitet. Wir speichern keine Kreditkartendaten und haben auch keinen Zugang zu deinen Kreditkartendaten.

Quantity Discount Promotion
🎯 BULK DISCOUNT: Buy More, Save More!
Buy 2 Items
5% OFF
Buy 4 Items
10% OFF
Buy 6 Items
15% OFF
✅ Auto-discount • 🔄 Mix & match
Expert

DIY Expert Support

Get fitment advice & recommendations

Mon-Fri, 8:30AM-8PM
WhatsApp WhatsApp Email
⚡
24-Hour Fast Ship
🚚
Arrives in 3-14 days
🌍
Global Reach
↩️
30-Day Returns
🌱 1 tree planted with every purchase

Beschreibung

M8 x 40mm Carriage Bolts Grade 8.8 — Reliable Fasteners for Wood Framing & Structural Joints

When a loose joint or a stripped bolt threatens your deck build, fence project, or workshop assembly, you need fasteners that hold without compromise. These M8 x 40mm carriage bolts are designed for DIYers, contractors, and woodworkers who demand consistent clamping force and a clean finished look — without spending extra time fighting a spinning bolt head.

Each 64-set includes M8 x 40mm Grade 8.8 carbon steel carriage bolts with a cup square dome head, paired with matching M8 hex nuts and flat washers. The M8 thread diameter measures 8mm (≈5/16") with a standard 1.25mm coarse pitch, and the 40mm (≈1-9/16") shank length suits material stacks up to approximately 30mm thick. Hardware is finished with a protective coating for general indoor and semi-exposed use.

Typical applications include deck rail connections, pergola and gazebo framing, fence post-to-rail joints, workbench assembly, and playground equipment repair — anywhere a flush, tamper-resistant bolt head and strong M8 carriage bolt for wood framing is required.

🔩 Thread Compatibility: Standard M8 × 1.25mm coarse thread — fits any M8 hex nut, coupling nut, or threaded insert. Square shank self-locks in wood; pre-drill a round hole equal to the bolt diameter.

✅ Key Features of These M8 Grade 8.8 Carriage Bolts

  • 🔒 Self-Locking Square Shank — The square neck under the dome head bites into wood on installation, preventing rotation so you can tighten the nut with one hand and no second wrench.
  • 💪 Grade 8.8 Structural Strength — Minimum 800 MPa tensile strength handles the shear and tension loads found in deck framing, fence construction, and carriage bolt structural wood joints.
  • 🧲 Smooth Dome Head Profile — The low-profile rounded head sits flush against the surface, eliminating sharp edges and giving a finished appearance on visible faces of furniture or outdoor structures.
  • 📦 Complete 64-Piece Hardware Set — Bolts, nuts, and washers are included together so you can start your project immediately without sourcing matching hardware separately.
  • 📐 Consistent M8 × 1.25mm Thread Pitch — Machined to standard metric coarse thread spec for reliable engagement with any M8-compatible nut, insert, or coupling across your project.
  • 🛡️ Protective Surface Finish — A zinc-based or equivalent coating provides a barrier against surface oxidation during storage and in covered outdoor applications such as pergola bolt kits and sheltered deck assemblies.

📐 Technical Specifications — M8 Carriage Bolt Set

Thread Standard Metric coarse — M8 × 1.25mm pitch
Bolt Length 40mm (≈1-9/16")
Thread Diameter 8mm (≈5/16")
Head Style Cup square dome (mushroom head)
Drive Style None — self-locking square shank (nut-side tightening only)
Strength Grade Grade 8.8 (min. tensile 800 MPa / yield 640 MPa)
Material Carbon steel with protective surface finish
Set Contents Carriage bolts, M8 hex nuts, flat washers — see variant options for piece count
Quantity per Set 64 pieces total
Recommended Hole Size 8mm (≈5/16") round clearance hole in wood
Suitable Material Thickness Up to approximately 30mm (≈1-3/16") combined stack
Finish / Coating See variant options
Indoor / Outdoor Use Indoor and semi-exposed outdoor (covered structures)
SKU XYHBRT4-331x3
⚠️ Spec Confirmation: Finish type and exact per-component piece count vary by variant. Please confirm with us before ordering for fully exposed or coastal outdoor applications.

❓ Frequently Asked Questions

How do I choose the right length for M8 carriage bolts?

Generally, the bolt length should equal the total thickness of the materials being joined plus enough thread engagement for the nut — typically an additional 10–15mm (about 3/8"–5/8"). For example, joining two 15mm boards would typically call for a bolt at least 40mm (≈1-9/16") long. The M8x40mm in this set suits material stacks up to approximately 30mm thick.

What does Grade 8.8 mean for carriage bolts?

Grade 8.8 is a medium-high strength classification for metric steel fasteners. It indicates a minimum tensile strength of 800 MPa and a yield strength of 640 MPa, making these bolts suitable for structural and load-bearing applications in wood, metal, and composite assemblies.

Can these carriage bolts be used outdoors?

These bolts are made from carbon steel with a protective finish that provides basic corrosion resistance for covered or semi-exposed outdoor use. For fully exposed environments — such as direct rain, coastal areas, or pressure-treated lumber — stainless steel fasteners are generally recommended for long-term durability.

What thread standard do these M8 carriage bolts use?

These bolts follow the standard metric coarse thread specification: M8 diameter with a 1.25mm pitch. They are compatible with any standard M8 hex nut or coupling nut. The included nuts in this set are matched to the same thread specification.

What is included in the 64-set?

Each 64-set typically includes M8x40mm carriage bolts, matching M8 hex nuts, and flat washers. The exact piece count per component is listed in the variant options. All hardware in the set shares the same M8 thread specification for direct interchangeability.

What is the cup square dome head design and why does it matter?

A cup square (also called mushroom or dome) head features a smooth, rounded top surface with a square shank section just below the head. The square shank bites into wood to prevent the bolt from spinning during tightening — no wrench needed on the bolt head. This makes installation faster and leaves a clean, snag-free surface on the visible side of the joint.

Are these bolts suitable for structural deck or fence building?

Yes. M8 Grade 8.8 carriage bolts are commonly used in deck framing, fence rail connections, pergola assembly, and similar structural wood applications. Always verify local building codes for minimum fastener requirements on load-bearing structures.

🛒 Select your size and quantity above, then add to cart — ships from our US warehouse.

You may also like

Recently viewed