{
 "version": "2026-10-20",
 "license": "Dimension sheets: CC BY 4.0. Standard and published-size files: CC BY 4.0. Xem Studio's own designs (files_license = Xem Studio Design License): free to use and sell things from, not to redistribute as files — https://xemstudio.com/license/. Other publishers' files: their own license, linked beside them.",
 "slug": "shoulder-screws-asme-b18-3",
 "name": "Shoulder screws ASME B18.3 (inch): shoulder Ø 1/4 to 3/4 in, thread, head size, hex key, thread length",
 "kind": "standard",
 "category": "Hardware",
 "group": "Fasteners",
 "year": null,
 "question": "What are the dimensions of an ASME B18.3 inch socket shoulder screw: shoulder diameter, thread, head diameter and height, hex key, thread length?",
 "tags": [
  "shoulder screw",
  "shoulder bolt",
  "asme b18.3",
  "socket head",
  "inch",
  "pivot",
  "standard",
  "fastener"
 ],
 "aliases": [
  "shoulder bolt dimensions inch",
  "shoulder screw dimensions",
  "1/4 shoulder bolt",
  "3/8 shoulder bolt dimensions",
  "1/2 shoulder bolt 3/8-16",
  "5/16 shoulder screw 1/4-20",
  "asme b18.3 shoulder screw",
  "shoulder bolt hex key size",
  "socket shoulder screw head diameter",
  "shoulder screw step",
  "shoulder bolt stl inch"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 6,
 "url": "https://xemstudio.com/objects/shoulder-screws-asme-b18-3/",
 "sheet_txt": "https://xemstudio.com/objects/shoulder-screws-asme-b18-3/sheet.txt",
 "sheet": {
  "basis": "ASME B18.3-2003 shoulder screw tables as published by AFT Fasteners and Holo-Krome; McMaster-Carr linked for CAD",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "ASME B18.3 socket shoulder screws: the shoulder diameter is the size name (1/4 in shoulder = #10-24 thread, 5/16 = 1/4-20, 3/8 = 5/16-18, 1/2 = 3/8-16, 5/8 = 1/2-13, 3/4 = 5/8-11). The shoulder is ground slightly under nominal (for 1/4 in: .2480 / .2460 max / min; 5/16: .3105 / .3085; 3/8: .3730 / .3710; 1/2: .4980 / .4960; 5/8: .6230 / .6210; 3/4: .7480 / .7450 or .7460), so a bore for it is nominal plus your clearance.",
   "Two independent tables (AFT Fasteners' B18.3-2003 sheet and Holo-Krome's shoulder screw sheet) agree on shoulder D max / min, head diameter A, head height H, hex key J, key engagement T and thread length E for all six sizes. Only the .7450 vs .7460 minimum for the 3/4 in shoulder differs. Other columns (neck diameters, fillet radii, chamfer C) are printed in both but their column assignment was ambiguous in extraction, so they are not used.",
   "Shoulder length is the dimension you select; the two sheets above do not print a length range, so no standard lengths are claimed here. Shoulder length tolerance: −.02 in up to 3/8 in shoulder, −.03 in above (AFT). McMaster-Carr carries these in inch sizes (shoulder length in 1/8 in or 1/4 in steps by size); the category links are below.",
   "Files: six solids, one per size, with an example 1 in (25.4 mm) shoulder length. Thread is drawn as a plain cylinder at the nominal major diameter (from the thread designation; #10 = .190 in) over the thread length E; head diameter and height are the maxima; socket depth is the minimum key engagement T. No chamfers, fillets or thread neck. Left out: larger shoulders (1 in and up), which neither sheet's text carried legibly.",
   "Metric ISO 7379 shoulder screws are on the companion page."
  ],
  "table": {
   "columns": [
    "shoulder Ø D (nominal)",
    "thread",
    "head Ø A (max), in (mm)",
    "head height H (max), in (mm)",
    "hex key J, in (mm)",
    "key engagement T (min), in",
    "thread length E, in (mm)"
   ],
   "rows": [
    [
     "1/4 (6.35 mm)",
     "#10-24",
     "0.375 (9.52)",
     "0.188 (4.78)",
     "1/8 (3.17)",
     "0.094",
     "0.375 (9.52)"
    ],
    [
     "5/16 (7.94 mm)",
     "1/4-20",
     "0.438 (11.13)",
     "0.219 (5.56)",
     "5/32 (3.97)",
     "0.117",
     "0.438 (11.13)"
    ],
    [
     "3/8 (9.52 mm)",
     "5/16-18",
     "0.562 (14.27)",
     "0.250 (6.35)",
     "3/16 (4.76)",
     "0.141",
     "0.500 (12.70)"
    ],
    [
     "1/2 (12.70 mm)",
     "3/8-16",
     "0.750 (19.05)",
     "0.312 (7.92)",
     "1/4 (6.35)",
     "0.188",
     "0.625 (15.88)"
    ],
    [
     "5/8 (15.88 mm)",
     "1/2-13",
     "0.875 (22.22)",
     "0.375 (9.52)",
     "5/16 (7.94)",
     "0.234",
     "0.750 (19.05)"
    ],
    [
     "3/4 (19.05 mm)",
     "5/8-11",
     "1.000 (25.40)",
     "0.500 (12.70)",
     "3/8 (9.52)",
     "0.281",
     "0.875 (22.22)"
    ]
   ]
  }
 },
 "sheet_text": "Shoulder screws ASME B18.3 (inch): shoulder Ø 1/4 to 3/4 in, thread, head size, hex key, thread length — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/shoulder-screws-asme-b18-3/  (sheet CC BY 4.0)\nBasis: ASME B18.3-2003 shoulder screw tables as published by AFT Fasteners and Holo-Krome; McMaster-Carr linked for CAD\nCatalog version: 2026-10-20\n\nSizes: see table below\n- ASME B18.3 socket shoulder screws: the shoulder diameter is the size name (1/4 in shoulder = #10-24 thread, 5/16 = 1/4-20, 3/8 = 5/16-18, 1/2 = 3/8-16, 5/8 = 1/2-13, 3/4 = 5/8-11). The shoulder is ground slightly under nominal (for 1/4 in: .2480 / .2460 max / min; 5/16: .3105 / .3085; 3/8: .3730 / .3710; 1/2: .4980 / .4960; 5/8: .6230 / .6210; 3/4: .7480 / .7450 or .7460), so a bore for it is nominal plus your clearance.\n- Two independent tables (AFT Fasteners' B18.3-2003 sheet and Holo-Krome's shoulder screw sheet) agree on shoulder D max / min, head diameter A, head height H, hex key J, key engagement T and thread length E for all six sizes. Only the .7450 vs .7460 minimum for the 3/4 in shoulder differs. Other columns (neck diameters, fillet radii, chamfer C) are printed in both but their column assignment was ambiguous in extraction, so they are not used.\n- Shoulder length is the dimension you select; the two sheets above do not print a length range, so no standard lengths are claimed here. Shoulder length tolerance: −.02 in up to 3/8 in shoulder, −.03 in above (AFT). McMaster-Carr carries these in inch sizes (shoulder length in 1/8 in or 1/4 in steps by size); the category links are below.\n- Files: six solids, one per size, with an example 1 in (25.4 mm) shoulder length. Thread is drawn as a plain cylinder at the nominal major diameter (from the thread designation; #10 = .190 in) over the thread length E; head diameter and height are the maxima; socket depth is the minimum key engagement T. No chamfers, fillets or thread neck. Left out: larger shoulders (1 in and up), which neither sheet's text carried legibly.\n- Metric ISO 7379 shoulder screws are on the companion page.\n\nshoulder Ø D (nominal)  thread  head Ø A (max), in (mm)  head height H (max), in (mm)  hex key J, in (mm)  key engagement T (min), in  thread length E, in (mm)\n1/4 (6.35 mm)  #10-24  0.375 (9.52)  0.188 (4.78)  1/8 (3.17)  0.094  0.375 (9.52)\n5/16 (7.94 mm)  1/4-20  0.438 (11.13)  0.219 (5.56)  5/32 (3.97)  0.117  0.438 (11.13)\n3/8 (9.52 mm)  5/16-18  0.562 (14.27)  0.250 (6.35)  3/16 (4.76)  0.141  0.500 (12.70)\n1/2 (12.70 mm)  3/8-16  0.750 (19.05)  0.312 (7.92)  1/4 (6.35)  0.188  0.625 (15.88)\n5/8 (15.88 mm)  1/2-13  0.875 (22.22)  0.375 (9.52)  5/16 (7.94)  0.234  0.750 (19.05)\n3/4 (19.05 mm)  5/8-11  1.000 (25.40)  0.500 (12.70)  3/8 (9.52)  0.281  0.875 (22.22)\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- AFT Fasteners: Socket shoulder screw dimensions (alloy steel), ASME B18.3-2003 — web — Publisher's page; dimensions are facts — https://aftfasteners.com/socket-shoulder-screws-dimensions-mechanical-properties\n- Holo-Krome (Global Industrial PDF): Socket shoulder screw dimensions (D, A, H, J, T, E) — web — Publisher's page; dimensions are facts — https://www.globalindustrial.com/site/images/holokrome/socketshoulder.pdf\n- McMaster-Carr: Steel shoulder screws (inch and metric) (free STEP/IGES per part, for your own design use; no redistribution) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution [verify license at link] — https://www.mcmaster.com/products/steel-shoulder-screws/\n- McMaster-Carr: Shoulder screws, ISO 7379 filter (free STEP/IGES per part, for your own design use; no redistribution) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution [verify license at link] — https://www.mcmaster.com/products/shoulder-screws/specifications-met~iso-7379\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 6 parts): https://xemstudio.com/files/hardware/shoulder-screws-asme-b18-3/index.json\nAPI: https://xemstudio.com/api/geometry?object=shoulder-screws-asme-b18-3\n",
 "sources": [
  {
   "publisher": "AFT Fasteners",
   "title": "Socket shoulder screw dimensions (alloy steel), ASME B18.3-2003",
   "url": "https://aftfasteners.com/socket-shoulder-screws-dimensions-mechanical-properties",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Holo-Krome (Global Industrial PDF)",
   "title": "Socket shoulder screw dimensions (D, A, H, J, T, E)",
   "url": "https://www.globalindustrial.com/site/images/holokrome/socketshoulder.pdf",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "McMaster-Carr",
   "title": "Steel shoulder screws (inch and metric) (free STEP/IGES per part, for your own design use; no redistribution)",
   "url": "https://www.mcmaster.com/products/steel-shoulder-screws/",
   "formats": [
    "STEP",
    "IGES",
    "PDF"
   ],
   "license": "McMaster-Carr site terms: personal design use, no redistribution",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "McMaster-Carr",
   "title": "Shoulder screws, ISO 7379 filter (free STEP/IGES per part, for your own design use; no redistribution)",
   "url": "https://www.mcmaster.com/products/shoulder-screws/specifications-met~iso-7379",
   "formats": [
    "STEP",
    "IGES",
    "PDF"
   ],
   "license": "McMaster-Carr site terms: personal design use, no redistribution",
   "license_verified": false,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "shoulder-screws-iso-7379",
  "socket-head-cap-screws-inch",
  "button-head-socket-screws-inch",
  "clevis-pins",
  "hex-bolts-inch",
  "imperial-machine-screws"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no tolerance added)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn.",
 "mating": [],
 "faq": [
  {
   "q": "What thread does a 1/2 in shoulder bolt have?",
   "a": "3/8-16 with a 0.625 in long thread, 3/4 in head Ø × 5/16 in tall (0.312), 1/4 in hex key."
  },
  {
   "q": "What hex key fits a 5/16 in shoulder screw?",
   "a": "5/32 in: the 5/16 in shoulder (1/4-20) screw has a .438 in head, .219 in tall, and a 5/32 in socket."
  },
  {
   "q": "What is the shoulder diameter tolerance?",
   "a": "Ground under nominal: 1/2 in shoulder is .4980 max / .4960 min."
  }
 ],
 "files_license": null,
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   "file": "shoulder-screw-b18-3-1-4in-shoulder-no10-24",
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   "license": "CC BY 4.0 (Xem Studio)",
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   "stl": "https://xemstudio.com/files/hardware/shoulder-screws-asme-b18-3/shoulder-screw-b18-3-1-4in-shoulder-no10-24.stl",
   "note": "ASME B18.3 shoulder screw, 1/4 in shoulder (Ø6.35 mm) × 1 in (25.4 mm) long, thread #10-24 × 0.375 in (9.52 mm) drawn as a plain Ø4.83 mm cylinder, head Ø0.375 × 0.188 in (max), 1/8 in hex socket 0.094 in deep (key engagement min); the 1 in shoulder length is an example, not a published value; no chamfers, fillets or thread neck"
  },
  {
   "file": "shoulder-screw-b18-3-5-16in-shoulder-1-4-20",
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   "note": "ASME B18.3 shoulder screw, 5/16 in shoulder (Ø7.94 mm) × 1 in (25.4 mm) long, thread 1/4-20 × 0.438 in (11.13 mm) drawn as a plain Ø6.35 mm cylinder, head Ø0.438 × 0.219 in (max), 5/32 in hex socket 0.117 in deep (key engagement min); the 1 in shoulder length is an example, not a published value; no chamfers, fillets or thread neck"
  },
  {
   "file": "shoulder-screw-b18-3-3-8in-shoulder-5-16-18",
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   "note": "ASME B18.3 shoulder screw, 3/8 in shoulder (Ø9.52 mm) × 1 in (25.4 mm) long, thread 5/16-18 × 0.500 in (12.70 mm) drawn as a plain Ø7.94 mm cylinder, head Ø0.562 × 0.250 in (max), 3/16 in hex socket 0.141 in deep (key engagement min); the 1 in shoulder length is an example, not a published value; no chamfers, fillets or thread neck"
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  {
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   "stl": "https://xemstudio.com/files/hardware/shoulder-screws-asme-b18-3/shoulder-screw-b18-3-1-2in-shoulder-3-8-16.stl",
   "note": "ASME B18.3 shoulder screw, 1/2 in shoulder (Ø12.70 mm) × 1 in (25.4 mm) long, thread 3/8-16 × 0.625 in (15.88 mm) drawn as a plain Ø9.52 mm cylinder, head Ø0.750 × 0.312 in (max), 1/4 in hex socket 0.188 in deep (key engagement min); the 1 in shoulder length is an example, not a published value; no chamfers, fillets or thread neck"
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   "stl": "https://xemstudio.com/files/hardware/shoulder-screws-asme-b18-3/shoulder-screw-b18-3-5-8in-shoulder-1-2-13.stl",
   "note": "ASME B18.3 shoulder screw, 5/8 in shoulder (Ø15.88 mm) × 1 in (25.4 mm) long, thread 1/2-13 × 0.750 in (19.05 mm) drawn as a plain Ø12.70 mm cylinder, head Ø0.875 × 0.375 in (max), 5/16 in hex socket 0.234 in deep (key engagement min); the 1 in shoulder length is an example, not a published value; no chamfers, fillets or thread neck"
  },
  {
   "file": "shoulder-screw-b18-3-3-4in-shoulder-5-8-11",
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   "stl": "https://xemstudio.com/files/hardware/shoulder-screws-asme-b18-3/shoulder-screw-b18-3-3-4in-shoulder-5-8-11.stl",
   "note": "ASME B18.3 shoulder screw, 3/4 in shoulder (Ø19.05 mm) × 1 in (25.4 mm) long, thread 5/8-11 × 0.875 in (22.22 mm) drawn as a plain Ø15.88 mm cylinder, head Ø1.000 × 0.500 in (max), 3/8 in hex socket 0.281 in deep (key engagement min); the 1 in shoulder length is an example, not a published value; no chamfers, fillets or thread neck"
  }
 ],
 "markdown": "https://xemstudio.com/objects/shoulder-screws-asme-b18-3/index.md"
}