M8 M10 M12 Carriage Bolts with Hex Nuts — Zinc-Plated Steel, Full & Partial Thread

A general rule is to add the thickness of all materials being joined, then add at least 1–2 thread pitches beyond the nut. For example, joining two 20mm (≈3/4") boards typically calls for a bolt of at least 50mm (≈2"): 40mm of material plus room for the nut and washer. When in doubt, size up — a bolt that's slightly long is easier to work with than one that's too short.

Full-thread bolts are threaded along their entire shank and are generally used for thinner materials or where maximum thread engagement is needed. Partial-thread bolts have a smooth shank section near the head that locks into the material, reducing the chance of the joint rotating under load — typically preferred for thicker timber connections such as deck ledger boards or post-to-beam joints.

The zinc-plated finish provides moderate corrosion resistance, making these bolts suitable for covered outdoor structures, interior framing, and dry exterior environments. For prolonged direct exposure to rain, coastal air, or pressure-treated lumber with copper-based preservatives (ACQ/CA), a hot-dip galvanized or stainless steel fastener is generally recommended for long-term durability.

Yes. These bolts follow the ISO metric coarse thread standard (DIN 603 / DIN 934 compatible). M8 bolts use a 1.25mm pitch, M10 a 1.5mm pitch, and M12 a 1.75mm pitch. They are compatible with standard metric hex nuts, flat washers, and lock washers available at any hardware store.

Load capacity depends on the bolt diameter, length, material grade, and installation method. These zinc-plated steel bolts are generally rated at Grade 4.8 or equivalent tensile strength. For structural or load-bearing applications — such as deck ledger connections or pergola post bases — consult a structural engineer and verify the grade marking on the bolt head before specifying.

Yes — each set includes matching zinc-plated hex nuts. The quantity of nuts corresponds to the number of bolts in your selected pack (e.g., a 10-piece pack includes 10 bolts and 10 nuts). Washers are not included and should be sourced separately if your application requires them.

M8 bolts are commonly used for light-to-medium timber framing, furniture assembly, and general DIY projects. M10 is a step up for heavier structural connections such as deck framing, gate hardware, or pergola rafters. M12 is typically chosen for heavy-duty applications like post bases, machinery mounting, or load-bearing brackets. When in doubt, check the specification of the bracket or hardware you are fastening to — it will usually call out the required bolt diameter.