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 — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/u-bolts-by-pipe-size/  (sheet CC BY 4.0)
Basis: Albany County Fasteners' U-bolt size chart (round pipe and square tubing), with one Zoro listing as a cross-check; numbers only
Catalog version: 2026-10-20

Sizes: see table below
- 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.

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"

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Albany County Fasteners: U-bolt size chart: round pipe and square tubing, U-bolt inside diameter, thread size, inside width range, thread length range — web — Distributor chart; numbers only — https://www.albanycountyfasteners.com/media/55/34/ee/1764619822/u-bolt-size-chart.pdf
- 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 — web — Retail listing; numbers only — https://www.zoro.com/zoro-select-14-20-x-38-pipe-size-black-oxide-u-bolt-10-pk-u172420250038/i/G9010836/

No true-size file yet: the published figures do not fix the whole shape; a measured scan is planned.
API: https://xemstudio.com/api/geometry?object=u-bolts-by-pipe-size