M10 x 42mm Inside (W) x 86mm Length (L) Galvanised Square U Bolts & Nuts

About Square U Bolts

Square U Bolts are bolts with a 90-degree square bend, designed to clamp square or rectangular hollow section (RHS / SHS) or angle to a structure. The square bend matches the flat face of the host section for full-contact clamping, where a round U bolt would only contact at two narrow tangent lines and crush the corners under load. Every Square U Bolt SKU on the BNA store ships as a pre-packed set with two matching nuts and washers - nyloc nuts with flat washers on most SKUs, or hex nuts with spring washers on the rest. Check the product page for the exact pack contents.

Not sure if this is the right U bolt?

Two ways to confirm before you order - whichever you already know.

1If you have the pipe or tube

Measure the outside diameter of the pipe, tube or shaft, then pick a U bolt whose Inside Width (W) matches or just clears it. The W value is printed in every product name (e.g. '40mm Inside (W)'), and the Length (L) is the leg length that passes through your plate or bracket.

2If you have a U bolt in hand

Three numbers identify it: the inside width between the legs (measured across the straight section, not the bend), the leg length from the crown down, and the diameter across the thread. Our step-by-step guide shows all three with drawings.

Open the U bolt measuring guide ›

Frequently Asked Questions

Material & Coating

Galvanised Hot-dip galvanised carbon steel. The standard outdoor finish; thick zinc coating gives decades of corrosion resistance. The right choice for trailer chassis, mast and pole mounting, structural pipe clamping and outdoor tank fittings.

Matching Finishes Always match the finish across the assembly. Hot-dip galvanising adds a much thicker coating than zinc plating, so a zinc-plated nut will not wind onto a galvanised bolt, and a galvanised nut on a zinc-plated bolt will be loose. Pair galvanised bolts with galvanised nuts and washers.

Important Performance in permanent coastal applications (within 300 metres of the sea) is reduced. Refer to AGA technical bulletins or contact us for the right grade for severe marine exposure.

Class Metric fasteners are classified as class 2, 4.6, 8.8, 10.9, 12.9, 14.9. See the head marking chart and full strength table.

Thread Pitch & Terminology

Thread Pitch (Metric) Metric fasteners measure thread pitch as the distance between thread peaks, expressed in millimetres. Metric also branches into three series: coarse (the default; widest tolerance, easiest to tap), fine (a tighter pitch for higher clamp load or thinner walls), and extra fine (the tightest pitch, used for thin-wall tube, precision instruments, and aerospace fittings where vibration loosening must be minimised). Always match the series as well as the size - a metric fine nut will not engage a metric coarse bolt of the same diameter, and an extra fine nut will not engage either. This product has a 1.50mm coarse pitch, meaning the peaks are 1.50mm apart.

How to Measure

Three numbers The inside width between the legs (measured across the straight section, not the bend), the leg length from the inside crown of the bend to the leg end, and the diameter across the outside of the thread - expect the reading a touch under the nominal size (an M10 reads between about 9.7mm and 10mm). The identification box near the top of this page shows all three on the drawing, and our U bolt measuring guide walks through them step by step.

Resources

Pricing & Delivery

Includes GST, a Tax Invoice and Free Standard Delivery anywhere in Australia.

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Disclaimer

Technical data Researched and compiled from numerous industry sources for the sole purpose of providing basic information. All material is advisory only and its use by anyone is entirely voluntary. Reliance on it for any purpose by anyone is at the sole risk of that person, and Bolt and Nut Australia is not responsible for any loss, claim or damages arising therefrom. In developing this information, Bolt and Nut Australia has made a determined effort to present it accurately.

Measurements Sizes are taken from supplier catalogues or hand-measured and should be used as a guide. Minor variation between batches is normal. Stock is sourced from various suppliers, so differences may exist between batches in thread length, markings, appearance or finish.

Product Photos & PDF Data Sheets Represent the product type, not exact size. PDFs are a reference guide only. Specifications may change without notice.

If you see any problems with any of our specifications or you require additional information please contact us.