Carriage bolts, ASME B18.5 round head square neck, #10 to 1 in: head, square neck, body diameter + envelope models — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/carriage-bolts-asme-b18-5/ (sheet CC BY 4.0) Basis: Brighton-Best's ASME B18.5 carriage bolt data sheet, cross-checked against Torqbolt's table (which adds the body diameter limits) and AFT Fasteners' thread-length rule; seven envelope models as files Catalog version: 2026-10-20 Overall (mm): length 21.4, width 21.4, height 81.5 - Dimensions are inches, round head square neck bolts, ASME B18.5, #10 to 1 in, each as max / min: head diameter A, head height H, square width O, square depth P (under the head) and the corner radius on the square R (max). Body diameter E max / min is from Torqbolt's table (threads are Unified UNC Class 2A per that page; for plated bolts it says the 2A maxima apply before plating). The two sheets agree on every value except two: the #10 head diameter minimum (.436 in Brighton-Best, .438 in Torqbolt) and the 7/8 head height maximum (.459 in Brighton-Best, .469 in Torqbolt); both are shown. The sheets label the columns with the standard's letters, but the letter-to-column mapping was not clear in the text read, so the columns are named by their position and size (square width ≈ the body diameter, e.g. .260 / .245 at 1/4, square depth .156 / .125). Check the standard if a figure matters. - Thread length (Brighton-Best): for nominal lengths 6 in and shorter the minimum thread length is twice the basic diameter plus 0.25 in; for longer bolts twice the basic diameter plus 0.50 in; carriage bolts are supplied fully threaded, very long ones may be threaded only 6 in. The AFT page, as read, gives the same 0.50 in rule above 6 in but printed 0.025 in (probably a typo for 0.25) for 6 in and shorter, so the Brighton-Best figure is used. Length is measured from under the head to the end. Length tolerances were not read. The mating square hole in a steel plate or the neck pocket in timber is not tabulated by these sources; use the square width O as the size to clear. - Not on this page: short neck, ribbed neck, fin neck and 114° countersunk square neck bolts (the page sources describe them but their tables could not be read reliably), and DIN 603 mushroom head square neck bolts (the DIN 603 table was not accessible). - Files are Xem-drawn envelopes: a spherical cap with base diameter A max and height H max, a square neck O max wide and P max deep, and a plain cylindrical shank at the nominal diameter; the head is the maximum limit because B18.5 gives no basic value. No thread, no chamfer, no corner radius, no point. The 3 in length under the head is an example chosen by Xem for all seven files, not a published length. Sizes drawn: #10, 1/4, 5/16, 3/8, 1/2, 5/8, 3/4. - McMaster-Carr sells carriage bolts with per-part STEP; the category is linked, not copied. Hex bolts: hex-bolts-inch; wood screws and lag screws: wood-screws-flat-head-inch, lag-screws-hex-inch. size (in) body E max / min head dia A max / min head height H max / min square width O max / min square depth P max / min corner radius on square max #10 .199 / .182 .469 / .436 .114 / .094 .199 / .185 .125 / .094 .031 1/4 .260 / .237 .594 / .563 .145 / .125 .260 / .245 .156 / .125 .031 5/16 .324 / .298 .719 / .688 .176 / .156 .324 / .307 .187 / .156 .031 3/8 .388 / .360 .844 / .782 .208 / .188 .388 / .368 .219 / .188 .047 7/16 .452 / .421 .969 / .907 .239 / .219 .452 / .431 .250 / .219 .047 1/2 .515 / .483 1.094 / 1.032 .270 / .250 .515 / .492 .281 / .250 .047 5/8 .642 / .605 1.344 / 1.219 .344 / .313 .642 / .616 .344 / .313 .078 3/4 .768 / .729 1.594 / 1.469 .406 / .375 .768 / .741 .406 / .375 .078 7/8 .895 / .852 1.844 / 1.719 .459 / .438 (Brighton-Best) or .469 / .438 (Torqbolt) .895 / .865 .469 / .438 .094 1 1.022 / .976 2.094 / 1.969 .531 / .500 1.022 / .990 .531 / .500 .094 Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - Brighton-Best: Carriage bolts product data sheet (ASME B18.5): head diameter, head height, square width, square depth, corner radius, #10 to 1 in; thread-length rule — web — Maker data sheet; numbers only — https://www.brightonbest.com/download/pds/Carriage Bolts.pdf - Torqbolt: ASME B18.5 round head square neck bolts: body diameter E max / min, head, square width and depth, corner radius, #10 to 1 in; UNC 2A thread note — web — Distributor page; numbers only — https://torqbolt.com/asme-b18-5-round-head-square-neck-bolts-dimensions-standards-specifications - AFT Fasteners: Carriage bolts: round head square neck, short neck, ribbed neck, fin neck, flat head (ASME B18.5); thread-length rule — web — Publisher's page; dimensions are facts — https://www.aftfasteners.com/carriage-bolts-dimensions-mechanical-properties/ Free files (CC BY 4.0, Xem Studio; STEP + STL, 7 parts): https://xemstudio.com/files/hardware/carriage-bolts-asme-b18-5/index.json API: https://xemstudio.com/api/geometry?object=carriage-bolts-asme-b18-5