Square U-Bolts with Plate and Nuts – M6 M8 M10 M12 Zinc Plated, Trailer & Pipe Clamp Fasteners

Match the thread diameter (M6, M8, M10, or M12) to your nut and plate hardware. The inside width (second number in the size code) should match the outer diameter of the pipe, tube, or axle you are clamping. The leg length should be long enough to pass through your mounting plate with sufficient thread engagement — typically at least 1.5× the thread diameter beyond the plate surface.

Example: M8 x 50 x 100mm = M8 thread, 50mm (≈2") inside width, 100mm (≈3.9") leg length. If your pipe OD is 48mm, this size would generally provide a snug fit.

Working load capacity depends on thread size, material grade, and installation torque. Generally, M6 zinc plated U-bolts are suited for light-duty clamping and small conduit; M8–M10 for medium loads such as trailer axle mounts and pipe supports; M12 for heavier structural and trailer applications. Always verify load requirements against your project specifications and apply appropriate safety factors. Contact us if you need grade or proof load data for a specific size.

The zinc electroplating provides corrosion resistance for general outdoor use in dry to moderately humid conditions — typical for trailers, garages, and outdoor structures. For prolonged exposure to saltwater, coastal air, or chemical environments, a stainless steel grade (304 or 316) is generally recommended. Inspect periodically and re-torque as needed, especially after the first few uses when the hardware seats in.

These U-bolts use standard ISO Metric Coarse thread — the most common metric thread standard used in automotive, trailer, and general fabrication work worldwide. M6, M8, M10, and M12 refer to the nominal thread diameter in millimeters. The included nuts and plates are matched to the same metric thread, so no conversion hardware is needed. They are not compatible with UNC/UNF (inch) threads.

Yes — square U-bolts are widely used to clamp round pipes, conduit, and round-section tubes. The inside width should match or very slightly exceed the outer diameter of the pipe for a secure, non-slip fit. They are also commonly used on trailer axles, leaf spring saddle mounts, and structural channel. The square bend profile is particularly well-suited to flat-plate mounting applications where a round-bend U-bolt would rock or shift.

The format is: Thread Diameter × Inside Width × Leg Length (all in millimeters).

• M8 — 8mm thread diameter (matches M8 nuts and wrenches)
• x 50 — 50mm (≈2") inside width between the two legs
• x 100mm — 100mm (≈3.9") leg length from the bend to the thread end

Choose inside width to match your pipe OD and leg length to suit your plate thickness plus the thread engagement you need.

Each set includes: 1× square U-bolt + 1× flat saddle plate + 2× hex nuts — a complete, ready-to-install assembly. The "Select Quantity" variant option lets you choose 1 set or 2 sets per order. If your application requires two U-bolts (e.g., both ends of a pipe clamp or a dual-bolt axle mount), select quantity 2 to receive two complete sets.