U-Bolt
Bolts · pipe clamp bolt · round bend u-bolt · square bend u-bolt
Definition: A U-bolt is a U-shaped bolt with threads on both legs, used to clamp a pipe, tube, or bundle to a flat surface with a plate and two nuts.
Anatomy
■ Head■ Shank■ Threads■ Point
Governing standards: Manufacturer specified (no universal standard)
Common Sizes
| Inch | Metric | Head width | Head height |
|---|---|---|---|
| 1/4-20 | M6 | for 3/8–1/2 pipe | 1–3 wide |
| 5/16-18 | M8 | for 3/4–1 pipe | 1–4 wide |
| 3/8-16 | M10 | for 1–2 pipe | 1–6 wide |
Representative sizes. Full dimensional data lives in the standards listed below.
Grades & Strength
| Grade | Material | Tensile (psi) | Marking |
|---|---|---|---|
| Zinc steel | carbon steel, zinc-plated | — | Indoor use |
| Stainless / galvanized | stainless or hot-dip galvanized | — | Outdoor / corrosive |
Materials
- Zinc-plated steel
- Stainless steel
- Hot-dip galvanized steel
Pros & Cons
Pros
- Clamps round objects securely
- Readily available by pipe size
- Simple plate + 2-nut install
Cons
- Rusts outdoors unless coated
- Sizing must match the pipe OD
- Plate can crush soft tubing if over-tightened
Typical Uses
- Exhaust and muffler clamps
- Pipe and conduit hangers
- Trailer and suspension mounting
- Clamping bundles and cables
Alternatives & Related
- Eye Bolt — Single-point attachment instead of a clamp
- Flange Bolt — Standard headed bolt for flat-surface joints
Where to Buy
Affiliate links — we may earn a commission at no cost to you.
FAQ
How do you measure a U-bolt?
By the pipe size it fits, the inside width, and the length of the threaded legs. Give all three when ordering a replacement.
What is a U-bolt used for?
Clamping round objects to a surface — exhaust pipes, conduits, tubing, and leaf springs on trailers and axles.