When a Standard U-Bolt Won't Fit
A U-bolt clamps a round or square section — pipe, tube, bar, a leaf spring, an exhaust, an antenna mast — down to a plate with a nut on each leg. The problem is that stock U-bolts only come in fixed inside widths, so the moment the thing you're clamping isn't a catalogue diameter, nothing fits: too loose and it slips, too tight and it won't go on.
EKINSUN makes the U-bolt to your dimensions instead — the exact inside width, leg length and thread, with the bend formed to the section you're clamping. Send a dimensioned sketch or the old U-bolt as a sample; no CAD file is needed, and one piece is fine.
Bend Shapes We Form
Round (semi-circular)
For round pipe and tube — the bend wraps the outside diameter closely
Semi-round
A round top with straight parallel legs for a deeper, more secure clamp
Square / rectangular
Right-angle bends to wrap square and rectangular tube or beams
Long-tangent
Extra leg length where the U-bolt has to reach through a thick mount
The Four Dimensions That Define a U-Bolt
Give us these four numbers — from a sketch or by measuring the old one — and we make a U-bolt that fits first time:
| Dimension | What it is |
|---|---|
| Rod diameter | Thickness of the bar, e.g. M8, M10, M12 — sets the strength |
| Inside width (A) | Distance across the inside of the legs — must match the section you clamp |
| Leg / thread length (B) | How far the legs reach and how much thread is needed for the plate and nuts |
| Thread | Metric (M) or imperial (UNC/UNF), rolled or cut on both legs |
Not sure of a dimension? Send the old U-bolt, or the pipe/tube you're clamping, and we measure it.
What the Catalogue Covers — and the Widths It Skips
Stock U-bolt inside widths track the standard steel pipe outside diameters — 21.3, 26.9, 33.7, 42.4, 48.3, 60.3, 76.1 and 88.9 mm in the EN 10255 series — because that is what most people clamp. Between those diameters the catalogue simply jumps, and that gap is where custom work starts:
| What you're clamping | In the catalogue today? | Sensible route |
|---|---|---|
| Standard pipe ODs — 21.3 to 88.9 mm series | Every clamp supplier stocks these widths | Buy it off the shelf — cheaper in the catalogue than machined |
| Popular trailer leaf-spring sizes | Trailer parts suppliers carry the common rod / width combinations | Buy if rod diameter and inside width both match; we bend when one doesn't |
| Solid bar, metric tube and in-between widths (e.g. 50, 62, 70 mm) | The catalogue jumps straight past them | Bent and threaded to your exact inside width |
| Square / rectangular tube beyond the small stocked range | Rarely stocked | Square-bend U-bolt formed to the profile |
| Long-tangent legs, extra thread length, 316 in odd sizes | Stocked only in common combinations | Made to your four dimensions |
| Obsolete OEM spring U-bolts | Dropped from spares lists | Reproduced from the old part — see obsolete fasteners |
Materials — Stainless for Marine & Exhaust
| Material | Best for |
|---|---|
| 316 stainless (1.4404, A4) | Marine, salt-water, chemical — maximum corrosion resistance |
| 304 stainless (1.4301, A2) | General outdoor, exhaust, food and washdown |
| Zinc-plated / galvanised steel | Structural and indoor clamping at lowest cost |
| Alloy steel | High-load leaf-spring and suspension U-bolts |
Replacing a worn or odd-size U-bolt? Send the old one — even corroded. We measure the rod diameter, inside width, leg length and thread and make a matching one, in an upgraded material if you want it to last longer. Same approach as our replacement bolts from a sample; no drawing needed via no-CAD ordering.
Typical Applications
- Pipe and tube clamping to a frame, wall or strut
- Leaf-spring and axle U-bolts for trailers and vehicles
- Exhaust and silencer mounting (stainless)
- Antenna, mast and pole mounting
- Marine rigging, rails and deck hardware (316)
- Machine guarding and cable/conduit support
Not exactly a U-bolt? We also make J-bolts, custom eye bolts, square U-bolts and custom bent rod to the same process. Describe the shape, or send a bent-wire sample, and we'll form it. See all custom fasteners.
What to Send Us
- Rod diameter (or the section size and load, and we'll advise)
- Inside width — across the inside of the legs
- Leg / thread length, and the thread size if you know it
- Bend shape (round, semi-round, square) — or the part you're clamping
- Material and finish, quantity, and delivery country
Frequently Asked Questions
Yes — the most common reason for a custom U-bolt. Stock U-bolts only come in fixed sizes, so when the pipe, tube or bar isn't a catalogue diameter we make the U-bolt to your exact inside width. Give us the dimension across the inside of the legs, or send the part you clamp.
All three. Round suits round pipe and tube; semi-round adds straight legs for a deeper clamp; square wraps square and rectangular tube. Tell us the profile you're clamping and we form the bend to match.
Yes — 316 stainless for marine and salt, 304 for general outdoor and exhaust, and zinc-plated or galvanised steel where cost matters. We pick the grade with you by corrosion, load and temperature.
Roughly M6 to M24 (1/4" to 1") rod, with metric or UNC/UNF threads on both legs to whatever length you need. We also make matching mounting plates (saddles) and supply nuts and washers on request.
CAD optional, and quantities from 1 piece to production volume. A dimensioned sketch — rod diameter, inside width, leg length, thread — or the old U-bolt as a sample is enough. A single replacement or a batch are both fine.
Get Custom U-Bolts Quoted
A sketch, a size or the old one — all accepted. Engineers reply in 12h.
// Qty & price
1 pc
Sample price
Confirm fit before a run
10–50
Unit price drops
Setup cost shared
100+
Best price
All tiers quoted upfront
- →No distributor — you pay the maker directly
- →Drawing saved after first order — reorder anytime at lower unit price