{
 "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": "wing-screws-inch-asme-b18-17",
 "name": "Wing screws, inch (type A, cold formed, ASME B18.17 family): #8 to 3/8 in wing spread, height, thickness, boss",
 "kind": "standard",
 "category": "Hardware",
 "group": "Fasteners",
 "year": null,
 "question": "How wide is a 1/4-20 wing screw, and how tall are its wings?",
 "tags": [
  "wing screw",
  "butterfly screw",
  "thumb screw wing",
  "wing bolt",
  "asme b18.17",
  "type a wing screw",
  "cold formed wing screw",
  "fastener",
  "inch"
 ],
 "aliases": [
  "wing screw dimensions inch",
  "1/4-20 wing screw wing span",
  "#10 wing screw size",
  "wing screw 5/16-18 dimensions",
  "3/8-16 wing screw wing height",
  "cold formed wing screw type a",
  "wing screw boss diameter",
  "butterfly screw size chart",
  "wing bolt dimensions 1/4",
  "asme b18.17 wing screw",
  "wing screw #8-32 wing spread",
  "wing screw thickness"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "not-scanned",
 "les": false,
 "free_files": 0,
 "url": "https://xemstudio.com/objects/wing-screws-inch-asme-b18-17/",
 "sheet_txt": "https://xemstudio.com/objects/wing-screws-inch-asme-b18-17/sheet.txt",
 "sheet": {
  "basis": "CDE Fasteners' type A wing screw sheet (ASME B18.6.8-2010 as printed) cross-checked with Tanner Bolt's cold-forged wing nut sheet (ASME B18.17), whose wing and boss dimensions are the same for the shared sizes; numbers only",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Inches (max / min in each cell; the last column converts the maxima of A and B to mm). Sizes #8 to 3/8 in. A wing spread, B wing height, C wing thickness, E boss diameter, G boss height. CDE prints the wing screw table under ASME B18.6.8-2010 (type A: a two-piece screw, cold-formed winged head permanently installed on the shank) and gives length tolerances by nominal length: ±0.03 in up to 1 in, ±0.06 over 1 to 2 in, ±0.09 over 2 in. No lengths are listed on that sheet.",
   "Cross-check: Tanner's cold-forged wing nut sheet (the ASME B18.17 table, already tabulated on wing-nuts-din-315-asme-b18-17) prints identical A, B, C, E and G max / min for #8, #10, 1/4, 5/16 and 3/8 (e.g. 1/4: A 1.10 / 0.97, B 0.57 / 0.43, C 0.18 / 0.14, E 0.50 / 0.45, G 0.22 / 0.17). The dimension D (between the wings), printed for wing nuts, is not on the wing screw sheet and is not shown. Types B and C (other head forms) were not found with numbers.",
   "No files: the wing outline (curve, cross-section) is not published as numbers in any table read, so no model is drawn. Metric forms: wing-screws-din-316. McMaster-Carr sells wing screws with per-part STEP; linked, not copied."
  ],
  "table": {
   "columns": [
    "size",
    "TPI",
    "A wing spread (in)",
    "B wing height (in)",
    "C wing thickness (in)",
    "E boss diameter (in)",
    "G boss height (in)",
    "mm (max)"
   ],
   "rows": [
    [
     "#8",
     "32",
     "0.91 / 0.78",
     "0.47 / 0.34",
     "0.14 / 0.10",
     "0.43 / 0.39",
     "0.18 / 0.14",
     "A 23.1 mm, B 11.9 mm"
    ],
    [
     "#10",
     "24 & 32",
     "0.91 / 0.78",
     "0.47 / 0.34",
     "0.14 / 0.10",
     "0.43 / 0.39",
     "0.18 / 0.14",
     "A 23.1 mm, B 11.9 mm"
    ],
    [
     "1/4",
     "20",
     "1.10 / 0.97",
     "0.57 / 0.43",
     "0.18 / 0.14",
     "0.50 / 0.45",
     "0.22 / 0.17",
     "A 27.9 mm, B 14.5 mm"
    ],
    [
     "5/16",
     "18",
     "1.25 / 1.12",
     "0.66 / 0.53",
     "0.21 / 0.17",
     "0.58 / 0.51",
     "0.25 / 0.20",
     "A 31.8 mm, B 16.8 mm"
    ],
    [
     "3/8",
     "16",
     "1.44 / 1.31",
     "0.79 / 0.65",
     "0.24 / 0.20",
     "0.70 / 0.64",
     "0.30 / 0.26",
     "A 36.6 mm, B 20.1 mm"
    ]
   ]
  }
 },
 "sheet_text": "Wing screws, inch (type A, cold formed, ASME B18.17 family): #8 to 3/8 in wing spread, height, thickness, boss — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/wing-screws-inch-asme-b18-17/  (sheet CC BY 4.0)\nBasis: CDE Fasteners' type A wing screw sheet (ASME B18.6.8-2010 as printed) cross-checked with Tanner Bolt's cold-forged wing nut sheet (ASME B18.17), whose wing and boss dimensions are the same for the shared sizes; numbers only\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Inches (max / min in each cell; the last column converts the maxima of A and B to mm). Sizes #8 to 3/8 in. A wing spread, B wing height, C wing thickness, E boss diameter, G boss height. CDE prints the wing screw table under ASME B18.6.8-2010 (type A: a two-piece screw, cold-formed winged head permanently installed on the shank) and gives length tolerances by nominal length: ±0.03 in up to 1 in, ±0.06 over 1 to 2 in, ±0.09 over 2 in. No lengths are listed on that sheet.\n- Cross-check: Tanner's cold-forged wing nut sheet (the ASME B18.17 table, already tabulated on wing-nuts-din-315-asme-b18-17) prints identical A, B, C, E and G max / min for #8, #10, 1/4, 5/16 and 3/8 (e.g. 1/4: A 1.10 / 0.97, B 0.57 / 0.43, C 0.18 / 0.14, E 0.50 / 0.45, G 0.22 / 0.17). The dimension D (between the wings), printed for wing nuts, is not on the wing screw sheet and is not shown. Types B and C (other head forms) were not found with numbers.\n- No files: the wing outline (curve, cross-section) is not published as numbers in any table read, so no model is drawn. Metric forms: wing-screws-din-316. McMaster-Carr sells wing screws with per-part STEP; linked, not copied.\n\nsize  TPI  A wing spread (in)  B wing height (in)  C wing thickness (in)  E boss diameter (in)  G boss height (in)  mm (max)\n#8  32  0.91 / 0.78  0.47 / 0.34  0.14 / 0.10  0.43 / 0.39  0.18 / 0.14  A 23.1 mm, B 11.9 mm\n#10  24 & 32  0.91 / 0.78  0.47 / 0.34  0.14 / 0.10  0.43 / 0.39  0.18 / 0.14  A 23.1 mm, B 11.9 mm\n1/4  20  1.10 / 0.97  0.57 / 0.43  0.18 / 0.14  0.50 / 0.45  0.22 / 0.17  A 27.9 mm, B 14.5 mm\n5/16  18  1.25 / 1.12  0.66 / 0.53  0.21 / 0.17  0.58 / 0.51  0.25 / 0.20  A 31.8 mm, B 16.8 mm\n3/8  16  1.44 / 1.31  0.79 / 0.65  0.24 / 0.20  0.70 / 0.64  0.30 / 0.26  A 36.6 mm, B 20.1 mm\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- CDE Fasteners: Wing screws type A, cold formed (sheet cites ASME B18.6.8-2010): wing spread A, height B, thickness C, boss E and G max / min, sizes 8 to 3/8 — web — Maker datasheet; numbers only — https://cdefasteners.com/sites/default/files/product-specs/wingscrtypea.pdf\n- Tanner Bolt (wing nut sheet, ASME B18.17): Cold-forged wing nuts: A, B, C, D, E, G (cross-check of the shared wing and boss dimensions) — web — Maker datasheet; numbers only — https://www.tannerbolt.com/media/akeneo_connector/Nutsforgedwing.pdf\n- McMaster-Carr: Wing screws (category) — web, STEP — McMaster-Carr site terms: personal design use, no redistribution [verify license at link] — https://www.mcmaster.com/wing-screws/\n\nNo true-size file yet: the published figures do not fix the whole shape; a measured scan is planned.\nAPI: https://xemstudio.com/api/geometry?object=wing-screws-inch-asme-b18-17\n",
 "sources": [
  {
   "publisher": "CDE Fasteners",
   "title": "Wing screws type A, cold formed (sheet cites ASME B18.6.8-2010): wing spread A, height B, thickness C, boss E and G max / min, sizes 8 to 3/8",
   "url": "https://cdefasteners.com/sites/default/files/product-specs/wingscrtypea.pdf",
   "formats": [
    "web"
   ],
   "license": "Maker datasheet; numbers only",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Tanner Bolt (wing nut sheet, ASME B18.17)",
   "title": "Cold-forged wing nuts: A, B, C, D, E, G (cross-check of the shared wing and boss dimensions)",
   "url": "https://www.tannerbolt.com/media/akeneo_connector/Nutsforgedwing.pdf",
   "formats": [
    "web"
   ],
   "license": "Maker datasheet; numbers only",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "McMaster-Carr",
   "title": "Wing screws (category)",
   "url": "https://www.mcmaster.com/wing-screws/",
   "formats": [
    "web",
    "STEP"
   ],
   "license": "McMaster-Carr site terms: personal design use, no redistribution",
   "license_verified": false,
   "hosted": false
  }
 ],
 "xem": {
  "status": "not-scanned",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "wing-screws-din-316",
  "wing-nuts-din-315-asme-b18-17",
  "thumb-screws-din-653-low-type",
  "knurled-thumb-screws-din-464",
  "imperial-machine-screws",
  "star-knobs-din-6336"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no tolerance added)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no tolerance added. 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. Typical accuracy by process and ISO 286 fits: https://xemstudio.com/tolerances/",
 "mating": [],
 "faq": [
  {
   "q": "How wide is a 1/4-20 wing screw?",
   "a": "Wing spread A is 1.10 in max / 0.97 in min (27.9 / 24.6 mm), wing height B 0.57 / 0.43 in (CDE sheet)."
  },
  {
   "q": "What are the boss dimensions of a #10 wing screw?",
   "a": "Boss E 0.43 / 0.39 in, boss height G 0.18 / 0.14 in."
  },
  {
   "q": "Are wing screws and wing nuts the same wing size?",
   "a": "Yes for the shared sizes: A, B, C, E and G match between CDE's wing screw sheet and Tanner's ASME B18.17 wing nut sheet."
  }
 ],
 "files_license": null,
 "offers": [],
 "markdown": "https://xemstudio.com/objects/wing-screws-inch-asme-b18-17/index.md"
}