{
 "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": "square-drive-iso-1174-1-4-to-1-in",
 "name": "Square drive sizes ISO 1174: 1/4, 3/8, 1/2, 3/4, 1 in drive (6.3, 10, 12.5, 20, 25 mm): male and female square limits + stub rail and pocket plate",
 "kind": "standard",
 "category": "Hardware",
 "group": "Hand tool interfaces",
 "year": null,
 "question": "What are the dimensions of a 1/4, 3/8, 1/2, 3/4 and 1 inch square drive (socket wrench square), male and female?",
 "tags": [
  "square drive",
  "socket drive",
  "ratchet",
  "1/4 drive",
  "3/8 drive",
  "1/2 drive",
  "iso 1174",
  "extension"
 ],
 "aliases": [
  "1/2 inch drive square size",
  "3/8 drive square dimension",
  "1/4 drive square size mm",
  "iso 1174",
  "socket drive size",
  "square drive dimensions",
  "3/4 drive square mm",
  "1 inch drive square size",
  "socket wrench square drive cad",
  "socket holder dimensions",
  "ratchet drive square stl",
  "socket rail design"
 ],
 "overall_mm": {
  "length": 121,
  "width": 41.4,
  "height": 18
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 2,
 "url": "https://xemstudio.com/objects/square-drive-iso-1174-1-4-to-1-in/",
 "sheet_txt": "https://xemstudio.com/objects/square-drive-iso-1174-1-4-to-1-in/sheet.txt",
 "sheet": {
  "basis": "ISO 1174-1:1996 free sample (male squares types A and B, female squares types C and D, separation force); two Xem-drawn example plates for rack and holder design",
  "overall_mm": {
   "length": 121,
   "width": 41.4,
   "height": 18
  },
  "notes": [
   "The square drive on ratchets, extensions and sockets is ISO 1174-1: nominal sizes 6.3, 10, 12.5, 20 and 25 mm, which are the 1/4, 3/8, 1/2, 3/4 and 1 in drives. The male square s1 is 6.35 / 9.53 / 12.70 / 19.05 / 25.40 mm at its maximum (the inch fractions to the hundredth) with the minimum 0.09 to 0.13 mm lower. The female square s2 limits (the hole in the socket) are above the male: 6.63 / 6.41, 9.80 / 9.58, 13.03 / 12.76, 19.44 / 19.11, 25.79 / 25.46 mm (max / min). The minimum separation force of the retaining detent is 4, 11, 25 and 45 N for 6.3, 10, 12.5 and 20 mm (no 25 mm value was readable).",
   "The standard's free sample prints other columns (the corner dimensions e1 and e2, the retaining hole d2, depths l2 and l3, corner radii r1 and r2), but the OCR of this sample is partly garbled and those columns could not be assigned to sizes with confidence, so they are not listed. The detent ball size and the retaining-hole position are not specified in the sample (the text only says a female square with a retaining hole, not a recess, is used with a plunger retainer), so no detent ball diameter is given: measure the ball on the tool you design to. McMaster-Carr and other catalogues list drive sizes only.",
   "Tool-holder use: a rack that holds sockets by the square needs a male stub of s1 max or slightly under (a socket's female square is s2 min or larger, and must slide over the post); a handle or adapter with a female square needs a hole of at least s2 min. The two plates are Xem examples drawn at true size: the stub rail posts at s1 max, the pocket plate holes at s2 min. For sockets that must grip, use the standard's separation force and your own detent.",
   "Not here: socket bodies and wall thickness (ASME B107.1), impact-socket squares and their pin holes (ISO 2725 / ASME B107.4 are separate standards), ratchet head sizes, spline and wobble drives, and 1-1/2 in and larger squares."
  ],
  "table": {
   "columns": [
    "nominal (mm)",
    "drive (in)",
    "male s1 max (mm)",
    "male s1 min (mm)",
    "female s2 max (mm)",
    "female s2 min (mm)",
    "min separation force (N)"
   ],
   "rows": [
    [
     "6.3",
     "1/4",
     "6.35",
     "6.26",
     "6.63",
     "6.41",
     "4"
    ],
    [
     "10",
     "3/8",
     "9.53",
     "9.44",
     "9.80",
     "9.58",
     "11"
    ],
    [
     "12.5",
     "1/2",
     "12.70",
     "12.59",
     "13.03",
     "12.76",
     "25"
    ],
    [
     "20",
     "3/4",
     "19.05",
     "18.92",
     "19.44",
     "19.11",
     "45"
    ],
    [
     "25",
     "1",
     "25.40",
     "25.27",
     "25.79",
     "25.46",
     "—"
    ]
   ]
  }
 },
 "sheet_text": "Square drive sizes ISO 1174: 1/4, 3/8, 1/2, 3/4, 1 in drive (6.3, 10, 12.5, 20, 25 mm): male and female square limits + stub rail and pocket plate — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/square-drive-iso-1174-1-4-to-1-in/  (sheet CC BY 4.0)\nBasis: ISO 1174-1:1996 free sample (male squares types A and B, female squares types C and D, separation force); two Xem-drawn example plates for rack and holder design\nCatalog version: 2026-10-20\n\nOverall (mm): length 121.0, width 41.4, height 18.0\n- The square drive on ratchets, extensions and sockets is ISO 1174-1: nominal sizes 6.3, 10, 12.5, 20 and 25 mm, which are the 1/4, 3/8, 1/2, 3/4 and 1 in drives. The male square s1 is 6.35 / 9.53 / 12.70 / 19.05 / 25.40 mm at its maximum (the inch fractions to the hundredth) with the minimum 0.09 to 0.13 mm lower. The female square s2 limits (the hole in the socket) are above the male: 6.63 / 6.41, 9.80 / 9.58, 13.03 / 12.76, 19.44 / 19.11, 25.79 / 25.46 mm (max / min). The minimum separation force of the retaining detent is 4, 11, 25 and 45 N for 6.3, 10, 12.5 and 20 mm (no 25 mm value was readable).\n- The standard's free sample prints other columns (the corner dimensions e1 and e2, the retaining hole d2, depths l2 and l3, corner radii r1 and r2), but the OCR of this sample is partly garbled and those columns could not be assigned to sizes with confidence, so they are not listed. The detent ball size and the retaining-hole position are not specified in the sample (the text only says a female square with a retaining hole, not a recess, is used with a plunger retainer), so no detent ball diameter is given: measure the ball on the tool you design to. McMaster-Carr and other catalogues list drive sizes only.\n- Tool-holder use: a rack that holds sockets by the square needs a male stub of s1 max or slightly under (a socket's female square is s2 min or larger, and must slide over the post); a handle or adapter with a female square needs a hole of at least s2 min. The two plates are Xem examples drawn at true size: the stub rail posts at s1 max, the pocket plate holes at s2 min. For sockets that must grip, use the standard's separation force and your own detent.\n- Not here: socket bodies and wall thickness (ASME B107.1), impact-socket squares and their pin holes (ISO 2725 / ASME B107.4 are separate standards), ratchet head sizes, spline and wobble drives, and 1-1/2 in and larger squares.\n\nnominal (mm)  drive (in)  male s1 max (mm)  male s1 min (mm)  female s2 max (mm)  female s2 min (mm)  min separation force (N)\n6.3  1/4  6.35  6.26  6.63  6.41  4\n10  3/8  9.53  9.44  9.80  9.58  11\n12.5  1/2  12.70  12.59  13.03  12.76  25\n20  3/4  19.05  18.92  19.44  19.11  45\n25  1  25.40  25.27  25.79  25.46  —\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- ISO (iTeh Standards free sample): ISO 1174-1:1996 square drive: male squares (types A, B) and female squares (types C, D), 6.3 to 25 mm, separation force — web — Standards body sample pages; dimensions are facts — https://cdn.standards.iteh.ai/samples/23590/fd20f8b72777452ba01817d07f90c2e8/ISO-1174-1-1996.pdf\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 2 parts): https://xemstudio.com/files/hardware/square-drive-iso-1174-1-4-to-1-in/index.json\nAPI: https://xemstudio.com/api/geometry?object=square-drive-iso-1174-1-4-to-1-in\n",
 "sources": [
  {
   "publisher": "ISO (iTeh Standards free sample)",
   "title": "ISO 1174-1:1996 square drive: male squares (types A, B) and female squares (types C, D), 6.3 to 25 mm, separation force",
   "url": "https://cdn.standards.iteh.ai/samples/23590/fd20f8b72777452ba01817d07f90c2e8/ISO-1174-1-1996.pdf",
   "formats": [
    "web"
   ],
   "license": "Standards body sample pages; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "hex-bit-shank-iso-1173-1-4-in",
  "hex-keys-iso-2936-asme-b18-3",
  "socket-head-cap-screws-metric"
 ],
 "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": [
  {
   "feature": "male square s1",
   "exact": "6.35 / 9.53 / 12.70 / 19.05 / 25.40 mm max (1/4, 3/8, 1/2, 3/4, 1 in)",
   "mates": "female square of a socket or adapter: s2 min 6.41 / 9.58 / 12.76 / 19.11 / 25.46 mm",
   "fit": "slide",
   "files": "square-drive-stub"
  },
  {
   "feature": "female square s2",
   "exact": "6.41 / 9.58 / 12.76 / 19.11 / 25.46 mm min",
   "mates": "male square on a ratchet, extension or stub: the male is s1 max or less",
   "fit": "slide",
   "files": "square-drive-female"
  }
 ],
 "fit_classes": {
  "press": "stays put: pin, tube, bearing or magnet held by interference. ISO 286 equivalent: H7/p6 (locational interference) or tighter.",
  "slide": "assembles by hand and is held by a grub, pinch or clamp: shaft in a hub, rod in a socket, spigot in a bore. ISO 286 equivalent: H7/g6 or H7/h6.",
  "run": "turns or slides in use: pin in a link, rod through a guide. ISO 286 equivalent: H8/f7 (close running).",
  "socket": "large sliding fit: syringe barrel, sleeve, bobbin in a bore. ISO 286 equivalent: H9/d9 (free running) or looser.",
  "clamp": "split part that closes on the mating part with screws: make it at size.",
  "designed": "a gap that is part of the design (piston fit option, displacer gap, air gap): do not change."
 },
 "faq": [
  {
   "q": "What size is a 3/8 inch square drive?",
   "a": "The male square is 9.53 mm (0.375 in) at its maximum and 9.44 mm at its minimum; the female square is 9.58 to 9.80 mm (ISO 1174-1, size 10)."
  },
  {
   "q": "What size is a 1/2 inch drive square?",
   "a": "12.70 mm max / 12.59 mm min male; 12.76 to 13.03 mm female; separation force at least 25 N."
  },
  {
   "q": "Is the detent ball size standardised?",
   "a": "Not in the free ISO 1174-1 sample used here: it does not specify the ball or the retaining hole, so measure the part you design to."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "square-drive-stub-rail-1-4-to-1",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/square-drive-iso-1174-1-4-to-1-in/square-drive-stub-rail-1-4-to-1.step",
   "stl": "https://xemstudio.com/files/hardware/square-drive-iso-1174-1-4-to-1-in/square-drive-stub-rail-1-4-to-1.stl",
   "note": "stub rail, 121.0 × 41.4 × 18.0 mm: five square posts at the ISO 1174-1 male square s1 max 6.35, 9.53, 12.70, 19.05 and 25.40 mm (1/4, 3/8, 1/2, 3/4, 1 in), 14 mm tall on a 4 mm base; base, post height and spacing are Xem choices, the post sizes are the standard's; add your process allowance only where a socket's female square must clear the post (the standard's own clearance is the s2 min)"
  },
  {
   "file": "square-drive-female-pocket-plate-1-4-to-1",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/square-drive-iso-1174-1-4-to-1-in/square-drive-female-pocket-plate-1-4-to-1.step",
   "stl": "https://xemstudio.com/files/hardware/square-drive-iso-1174-1-4-to-1-in/square-drive-female-pocket-plate-1-4-to-1.stl",
   "note": "female square pocket plate, 111.3 × 39.5 × 10 mm: five through square holes at the ISO 1174-1 female s2 min 6.41, 9.58, 12.76, 19.11 and 25.46 mm, smallest first; plate size and thickness are Xem choices"
  }
 ],
 "markdown": "https://xemstudio.com/objects/square-drive-iso-1174-1-4-to-1-in/index.md"
}