304 Stainless Steel Square U-Bolts — Secure Any Pipe, Rail, or Tube with Confidence
Whether you're mounting conduit in a workshop, securing fence rails outdoors, or building a custom rack system, finding a U-bolt that won't rust, strip, or loosen over time is half the battle. These A2 304 stainless steel square U-bolts are built for DIYers, fabricators, and tradespeople who need a reliable metric fastener that holds up in real-world conditions.
Each square U-bolt is machined from solid A2 (Grade 304) stainless steel with ISO metric coarse threads. Available in M6, M8, M10, and M12 diameters with thread pitches of 1.0mm, 1.25mm, 1.5mm, and 1.75mm respectively. Inner span widths range from 50mm (≈1.97") to 210mm (≈8.27"), and threaded leg lengths range from 20mm (≈0.79") to 160mm (≈6.30"), giving you precise sizing for a wide range of clamping applications. Sold individually (1 pc) or in pairs (2 pcs) depending on the variant selected.
Typical use cases include pipe and conduit mounting in electrical and plumbing installations, square tube clamping for custom metal fabrication and racking systems, and outdoor structural fastening for fencing, pergolas, and garden structures where corrosion-resistant square U-bolt hardware is essential.
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Thread Compatibility: ISO metric coarse thread — M6 (1.0mm pitch), M8 (1.25mm pitch), M10 (1.5mm pitch), M12 (1.75mm pitch). Compatible with standard metric hex nuts and flat washers.
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Size Note: The Size format is M[diameter] × [leg length] × [inner span]. Example: M8x50x80mm = M8 bolt, 50mm threaded leg, 80mm (≈3.15") inner span. Measure your pipe or tube OD before selecting a size. Contact us to confirm if unsure.
✅ Key Features of These 304 Stainless Steel Square U-Bolts
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🦾A2 Grade 304 Stainless Steel — Resists rust, oxidation, and surface staining in outdoor, humid, and light marine environments without surface coatings.
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📐Square-Bend Profile — Flat inner legs grip square and rectangular tubing securely, preventing rotation and providing even clamping pressure across the contact surface.
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🔧ISO Metric Coarse Threads — Standard metric thread pitch on each leg ensures compatibility with off-the-shelf metric hex nuts, lock nuts, and flat washers for stainless steel pipe clamp assemblies.
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📏Wide Size Range (M6–M12) — Covers inner spans from 50mm to 210mm and leg lengths from 20mm to 160mm, making these square U-bolt fasteners suitable for light conduit work up to heavy structural clamping.
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🔁Flexible Quantity Options — Available in 1-piece or 2-piece packs so you can order exactly what your project requires without overstocking hardware.
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🏗️Versatile Installation — Suited for pipe mounting brackets, fence rail clamps, custom fabrication jigs, and outdoor structural fastening where a metric square U-bolt with corrosion resistance is required.
📐 Technical Specifications — Square U-Bolt Fasteners
| Material |
A2 Grade 304 Stainless Steel |
| Bolt Diameters Available |
M6, M8, M10, M12 |
| Thread Pitch |
M6: 1.0mm | M8: 1.25mm | M10: 1.5mm | M12: 1.75mm |
| Thread Standard |
ISO Metric Coarse |
| Bend Style |
Square (right-angle) bend |
| Inner Span Range |
50mm (≈1.97") – 210mm (≈8.27") — see variant options |
| Threaded Leg Length Range |
20mm (≈0.79") – 160mm (≈6.30") — see variant options |
| Surface Finish |
Mill / brushed stainless (no additional coating) |
| Nuts / Washers Included |
Contact us to confirm |
| Pack Quantity |
1 pc or 2 pcs — select via Amount(pcs) option |
| Corrosion Resistance |
Good — suitable for outdoor and light marine use |
| Country of Origin |
See variant options |
❓ Frequently Asked Questions
How do I choose the right size square U-bolt for my application?
The Size option uses the format M[diameter] × [leg length] × [inner span]. For example, M8x50x80mm means an M8 bolt with 50mm of threaded leg and an 80mm (≈3.15") inner span between the two legs. Match the inner span to the outer dimension of the pipe, tube, or bar you are clamping. When in doubt, measure your material's outer dimension and select the next size up for a comfortable fit.
What load can these square U-bolts handle?
Load capacity depends on bolt diameter, thread engagement depth, and the material being clamped. Generally, M6 U-bolts are suited for light-duty conduit and pipe work, M8–M10 for medium structural loads, and M12 for heavier clamping applications. For safety-critical or load-bearing installations, we recommend consulting a qualified engineer to verify the appropriate fastener specification.
Are these U-bolts suitable for outdoor or marine use?
Yes. A2 (Grade 304) stainless steel provides good corrosion resistance in most outdoor environments, including garden structures, fencing, and light coastal applications. For highly aggressive saltwater immersion or chemical exposure, A4 (Grade 316) stainless is typically recommended. These bolts are well-suited for general outdoor and light marine use.
What thread standard do these U-bolts use, and are they compatible with standard nuts?
These U-bolts use standard ISO metric coarse threads: M6 at 1.0mm pitch, M8 at 1.25mm pitch, M10 at 1.5mm pitch, and M12 at 1.75mm pitch. They are compatible with standard metric hex nuts, nylon lock nuts, and flat washers available at most hardware stores.
Do the U-bolts come with nuts and washers?
Nuts and washers are generally not included unless stated in the specific variant listing. Please contact us before ordering if you need confirmation on what hardware is included with your selected size and quantity.
What does the Size format M6x20x50mm mean exactly?
The format is M[bolt diameter] × [threaded leg length] × [inner span width]. So M6x20x50mm means: M6 bolt diameter, 20mm (≈0.79") of threaded leg on each side, and a 50mm (≈1.97") inner span between the two legs. Select the inner span to match the outer dimension of the pipe, tube, or bar you are securing.
Can I use square U-bolts to clamp round pipe?
Square U-bolts are designed primarily for square and rectangular tubing or bar stock. They can be used on round pipe in some non-critical applications, but a round-bend U-bolt typically provides a better fit and more even clamping pressure on round pipe. Contact us if you need help selecting the right U-bolt style for your specific pipe or tube.
🛒 Select your size, thread pitch, and quantity above, then add to cart — ships from our US warehouse.
