Metallics UBS516134 Bolts 5/16-18 x 2-11/16 x 1-3/4 U-Bl SS (Box 50)

The UBS516134 is a 5/16-18 U-bolt with a 1-3/4 inch inside width and 2-11/16 inch leg length, so it wraps round stock, conduit, or pipe up to about 1-3/4 inches outside diameter. Anything larger will not seat between the legs, and much smaller stock leaves the saddle loose unless you shim it.

Material is 18-8 stainless steel, the standard austenitic grade for general corrosion resistance, so it holds up outdoors, in damp mechanical and boiler rooms, and on rooftop conduit runs where plated carbon steel would rust. For chloride-heavy coastal or pool environments, a 316 stainless fastener is the better call.

Each U-bolt ships with two hex nuts, one per leg, so no separate nut order is needed. If your mounting channel or bracket needs washers to spread the load across a slot, those are not part of the assembly.

They come 50 pieces to a box, and 50 each is the order minimum, so the box is the buying unit. Box weight is 3175 g. For other sizes or pack quantities in the UBS series, Metallics makes them available by request.

It is flagged compliant for both Buy American and ARRA, which is what a government, school, or healthcare procurement file usually needs on a fastener line item. Country of origin is listed as multiple.

Threads are to ANSI/ASME B1.1, the hex nut dimensions follow ASME B18.2.2, and the stainless nut material is to ASTM F594. That trio is normally enough to close out a fastener submittal on a mechanical or electrical package.

A U-bolt like this 5/16-18 stainless unit clamps all the way around the pipe and bolts through a plate or strut from both sides, so it resists pull-out and lateral movement better than a one-sided strap. Use a strap when you are fastening flat to a wall or joist face with no back access, and use the U-bolt when you have a bracket, angle, or channel you can pass both legs through and get nuts on the far side. Both nuts are included here.

The hex nuts measure 0.489 to 0.500 inch across the flats, which is a 1/2 inch wrench or socket. Nut height runs 0.258 to 0.273 inch. Those are standard 5/16-18 hex nut dimensions, so a replacement off the shelf will fit.

It is sold through the electrical side but the stated field application covers the electrical, plumbing, heating, and air conditioning trades. In practice it is a general purpose stainless clamp for securing conduit, pipe, tubing, or round stock to a bracket, strut, or plate.