Product and application brief
A U-bolt is formed from a rod with two threaded legs connected by a bend. Round-bend and square-bend parts are distinct geometries. Standard patterns and custom drawings are identified by the complete bend and leg dimensions, not only the thread size.
Product forms and reference names
| Product form / field | Reference and distinguishing details |
|---|---|
| Round-bend U-bolts | A curved crown around a round mating profile. Haydon lists round-bend products separately from square-bend products. Nominal pipe size does not replace the actual dimensional record. |
| Square-bend U-bolts | A flatter crown and two corners for a different mating profile. The corners retain a bend radius; square bend does not mean perfectly sharp internal corners. |
| Other bent-bolt forms | ASME B18.31.5, Bent Bolts (Inch Series), includes differing U-bolt bends and additional forms. Use the exact selected form rather than treating the standard number as one geometry. |
| Drawing-based U-bolts | Non-catalog widths, unequal or specified leg lengths, bend profiles and accessory arrangements need a dimensioned drawing. |
Inside width versus centre spacing
Inside width is the clear distance between the inner leg surfaces. Centre-to-centre leg spacing uses the rod centre lines. Identify which dimension is being supplied; neither should be replaced by a bare pipe-size label.
Length and bend convention
Show whether length refers to overall outside height, inside height or straight leg length. Include the bend radius or mating-profile dimensions and the thread length on each leg. Different catalog drawings can use different letters and conventions.
Rod, finish and accessories
Specify rod material or grade, thread designation and finish. If a plate, saddle, nuts or washers are needed, list their drawing and quantities separately. A U-bolt-only item and a complete clamping assembly are different order units. No allowable load or installation torque is inferred from the shape.
Specification fields
| Product form / field | Reference and distinguishing details |
|---|---|
| Bend | Round, square or drawing-defined profile; bend radius and mating geometry. |
| Rod / thread | Rod diameter, metric or inch thread, pitch and thread length for each leg. |
| Width | Inside clear width and/or centre-to-centre spacing, explicitly labelled. |
| Height / legs | Overall or inside height, straight leg length and any unequal-leg requirement. |
| Material / finish | Specified material or grade and selected surface treatment. |
| Accessories / quantity | Bolt, plate/saddle and fasteners identified separately; pieces or assembly units. |
Common product questions
Does a thread size identify a U-bolt?
No. Bend shape, inside width, height and thread length are also required.
Are round-bend and square-bend U-bolts interchangeable?
Not by name alone. Compare the mating profile, bend radius, spacing and complete dimensions.
Does ASME B18.31.5 imply that every size is stocked?
No. ASME explicitly distinguishes dimensional configurations from stock production sizes. A standard reference is not an availability claim.
Related bolt types
Product references
References checked 5 October 2026 explain product identity. Third-party model names and approvals are not FastenerBridge brand affiliation, stock or certification claims. Final geometry and requirements follow the selected specification.