# U-bolts by pipe size: thread, inside diameter, inside width and thread length for 1/2 to 6 in pipe and 1 to 3 in square tube

> What size U-bolt do I need for a 2 in pipe, and what thread and inside width does it have?

- Category: Hardware › Fasteners
- Kind: Standard part
- Basis: Albany County Fasteners' U-bolt size chart (round pipe and square tubing), with one Zoro listing as a cross-check; numbers only
- Page: https://xemstudio.com/objects/u-bolts-by-pipe-size/ · JSON: https://xemstudio.com/api/geometry?object=u-bolts-by-pipe-size · Plain text: https://xemstudio.com/objects/u-bolts-by-pipe-size/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- Rows are the distributor's chart, inches: for each nominal pipe size the pipe outside diameter, the U-bolt inside diameter, the thread size, the inside width (leg spacing) as a range and the thread length as a range. Ranges are the available sizes the chart prints, not tolerances. The chart prints two thread sizes for 1-1/4 in pipe (3/8-16 or 1/2-13). Square tubing rows give the U-bolt's inside dimension, thread, inside width and thread length. The chart has no overall height / length column, so none is given here; U-bolts are also made to order in other lengths.
- Cross-check: a Zoro Select U-bolt for 3/8 in pipe prints thread 1/4-20, inside width 3/4 in, inside height 2-1/4 in, thread length 1-1/2 in. That size is not in the Albany chart (which starts at 1/2 in pipe and 3/8-16). The Albany chart's 1/2 and 3/4 in pipe rows use a 3/8-16 thread; other makers, for example the Anvil Fig. 137 listing at 3/4 in pipe with a 1/4 in thread (title only, no table read), use lighter rods, so the thread depends on the maker and load.
- The chart's own notes (not Xem's): use a backing plate or saddle to spread clamping force and avoid distorting the pipe; measure the outside diameter including insulation on insulated pipe; thread engagement in the nut at least 1.5 × bolt diameter; inside width should accommodate the backing plate plus 1/4 to 1/2 in of clearance. Torque figures on the chart were not read and are not given.
- Not on this page: bend radius, overall length, ASME / ISO U-bolt standards (none was read) and load ratings. No file: the U-bolt bend and thread are not given as a complete set of numbers by the sources read, so a drawing would be invented. Pipe OD itself: asme-b16-5-flange-bolt-patterns and emt-conduit; wire rope U-bolt clips: wire-rope-clips-crosby-g450-g429. McMaster-Carr sells U-bolts with per-part STEP; its category is linked, not copied.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| inside diameter | 2 in pipe (OD 2.375 in): inside dia 2-1/2 in; 4 in pipe (OD 4.500 in): 4-1/2 to 5 in (Albany County Fasteners chart) | steel pipe of the nominal size (round pipe rows) or tube of the listed section (square rows) | clamp | all |
| thread | 3/8-16 (1/2 to 1 in pipe), 1/2-13 (1-1/2 and 2 in), 5/8-11 (2-1/2 and 3 in), 3/4-10 (4 and 5 in), 7/8-9 (6 in) | UNC nut and washer / backing plate of the same thread (hex-nuts-inch, flat-washers-inch) | designed | all |

## Sizes

| support | nominal size | pipe OD | U-bolt inside dia | thread | inside width | thread length |
|---|---|---|---|---|---|---|
| round pipe (NPS) | 1/2" | 0.840" | 7/8" to 1" | 3/8"-16 | 1-1/4" to 2" | 2" to 3" |
| round pipe (NPS) | 3/4" | 1.050" | 1-1/8" to 1-1/4" | 3/8"-16 | 1-1/2" to 2" | 2" to 3" |
| round pipe (NPS) | 1" | 1.315" | 1-3/8" to 1-1/2" | 3/8"-16 | 1-3/4" to 2-1/2" | 2-1/2" to 3-1/2" |
| round pipe (NPS) | 1-1/4" | 1.660" | 1-3/4" | 3/8"-16 or 1/2"-13 | 2" to 3" | 2-1/2" to 3-1/2" |
| round pipe (NPS) | 1-1/2" | 1.900" | 2" | 1/2"-13 | 2-1/4" to 3" | 3" to 4" |
| round pipe (NPS) | 2" | 2.375" | 2-1/2" | 1/2"-13 | 2-1/2" to 3-1/2" | 3" to 4" |
| round pipe (NPS) | 2-1/2" | 2.875" | 3" | 5/8"-11 | 3" to 4" | 3-1/2" to 5" |
| round pipe (NPS) | 3" | 3.500" | 3-1/2" to 4" | 5/8"-11 | 3-1/2" to 5" | 4" to 6" |
| round pipe (NPS) | 4" | 4.500" | 4-1/2" to 5" | 3/4"-10 | 4" to 6" | 4" to 6" |
| round pipe (NPS) | 5" | 5.563" | 5-1/2" to 6" | 3/4"-10 | 5" to 7" | 5" to 7" |
| round pipe (NPS) | 6" | 6.625" | 6-1/2" to 7" | 7/8"-9 | 6" to 8" | 6" to 8" |
| square tubing | 1" × 1" | — | 1" × 1" | 3/8"-16 | 2" to 2-1/2" | 2-1/2" to 3" |
| square tubing | 1-1/4" × 1-1/4" | — | 1-1/4" × 1-1/4" | 3/8"-16 | 2-1/4" to 3" | 2-1/2" to 3-1/2" |
| square tubing | 1-1/2" × 1-1/2" | — | 1-1/2" × 1-1/2" | 1/2"-13 | 2-1/2" to 3-1/2" | 3" to 4" |
| square tubing | 2" × 2" | — | 2" × 2" | 1/2"-13 | 3" to 4" | 3" to 4" |
| square tubing | 2-1/2" × 2-1/2" | — | 2-1/2" × 2-1/2" | 5/8"-11 | 3-1/2" to 5" | 4" to 5" |
| square tubing | 3" × 3" | — | 3" × 3" | 5/8"-11 | 4" to 6" | 4" to 6" |
| Zoro listing (cross-check, 'pipe size' 3/8 in) | 3/8" | — | — | 1/4"-20 | 3/4" (inside height 2-1/4") | 1-1/2" |

## Where the files are

- Albany County Fasteners: [U-bolt size chart: round pipe and square tubing, U-bolt inside diameter, thread size, inside width range, thread length range](https://www.albanycountyfasteners.com/media/55/34/ee/1764619822/u-bolt-size-chart.pdf) — web — Distributor chart; numbers only
- Zoro (Zoro Select listing): [Round U-bolt 1/4-20 for 3/8 in pipe: inside width 3/4 in, inside height 2-1/4 in, thread length 1-1/2 in](https://www.zoro.com/zoro-select-14-20-x-38-pipe-size-black-oxide-u-bolt-10-pk-u172420250038/i/G9010836/) — web — Retail listing; numbers only

## Questions

**What U-bolt fits 2 in pipe?**

Albany County Fasteners' chart: inside diameter 2-1/2 in, thread 1/2-13, inside width 2-1/2 to 3-1/2 in, thread length 3 to 4 in (pipe OD 2.375 in).

**What thread does a U-bolt for 4 in pipe use?**

3/4-10 on the chart, inside diameter 4-1/2 to 5 in, inside width 4 to 6 in, thread length 4 to 6 in.

**What is the inside width of a U-bolt?**

The leg spacing: the chart prints ranges, for example 1-3/4 to 2-1/2 in for 1 in pipe and 3-1/2 to 5 in for 3 in pipe.

## Fits with

- [Wire rope clips: Crosby G-450 U-bolt and G-429 Fist Grip dimensions by rope size, clips required, turn back and torque](https://xemstudio.com/objects/wire-rope-clips-crosby-g450-g429/)
- [Hex nuts, inch: #4-40 to 3/4-10 (ASME B18.2.2)](https://xemstudio.com/objects/hex-nuts-inch/)
- [Flat washers, inch: SAE and USS, 1/4 to 3/4 in (ASME B18.21.1 Type A)](https://xemstudio.com/objects/flat-washers-inch/)
- [Threaded rod, metric: M4 × 194.2](https://xemstudio.com/objects/threaded-rods-metric/)
- [Strut channel, 1-5/8 in (Unistrut / B-Line): profile, lips, slots and hole patterns](https://xemstudio.com/objects/strut-channel-1-5-8/)
- [EMT conduit sizes: 1/2 to 2 in OD and wall (ANSI C80.3)](https://xemstudio.com/objects/emt-conduit/)
- [Steel pipe ASME B36.10M: OD and wall thickness by NPS and schedule (Sch 10, 40, STD, 80, XS, 160, XXS), NPS 1/8 to 24 + hollow pipe STEP/STL](https://xemstudio.com/objects/steel-pipe-asme-b36-10m-nps-1-8-to-24/)