{
 "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": "inch-keys-square-rectangular-ansi-b17-1",
 "name": "Inch square and rectangular keys to 1-1/2 in (ANSI B17.1): 3/4, 7/8, 1, 1-1/4, 1-1/2 in square, 1/2 x 3/8, 1 x 3/4 in rectangular keys, shaft range and keyseat depth",
 "kind": "standard",
 "category": "Hardware",
 "group": "Gears, cranks & flywheels",
 "year": null,
 "question": "What key size goes with a 2 in, 3 in or 4 in shaft (ANSI B17.1): square key width, rectangular key height and keyseat depth?",
 "tags": [
  "inch keys",
  "ANSI B17.1",
  "square key",
  "rectangular key",
  "keyseat",
  "key size for shaft",
  "3/4 square key",
  "1 inch square key",
  "1/2 x 3/8 key",
  "keyboard"
 ],
 "aliases": [
  "1/2 x 1/2 square key",
  "5/8 square key",
  "3/4 square key",
  "7/8 square key",
  "1 inch square key",
  "1-1/4 square key",
  "1-1/2 square key",
  "1/2 x 3/8 rectangular key",
  "3/4 x 1/2 key",
  "1 x 3/4 key",
  "key size for 2 inch shaft",
  "key size for 3 inch shaft",
  "key size for 4 inch shaft",
  "key size for 1-1/2 inch shaft",
  "key size for 1-3/4 shaft",
  "keyseat depth 2 inch shaft",
  "keyseat depth 1 inch shaft",
  "ANSI B17.1 key chart",
  "shaft diameter to key size chart",
  "rectangular key vs square key",
  "keyway depth for 1-1/2 shaft",
  "inch key dimensions",
  "key size 5/8 shaft",
  "1 inch shaft key size"
 ],
 "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/inch-keys-square-rectangular-ansi-b17-1/",
 "sheet_txt": "https://xemstudio.com/objects/inch-keys-square-rectangular-ansi-b17-1/sheet.txt",
 "sheet": {
  "basis": "ANSI B17.1 shaft-to-key table (Engineers Edge and GlobalSpec agree) with Engineers Edge keyseat S / T depths cross-checked by T - S = H + 0.005; numbers only",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Keyseat depths in inches from Engineers Edge (nominal shaft: key square / rectangular; S shaft keyseat square and rectangular; T hub keyseat, parallel, square and rectangular): 1-3/4: 3/8 sq / 3/8 x 1/4, S 1.542 / 1.605, T 1.922 / 1.860; 2: 1/2 sq / 1/2 x 3/8, S 1.718 / 1.781, T 2.223 / 2.161; 2-1/4: 1/2 sq / 1/2 x 3/8, S 1.972 / 2.034, T 2.477 / 2.414; 2-1/2: 5/8 sq / 5/8 x 7/16, S 2.148 / 2.242, T 2.778 / 2.684; 3: 3/4 sq / 3/4 x 1/2, S 2.577 / 2.702, T 3.332 / 3.207; 3-1/2: 7/8 sq / 7/8 x 5/8, S 3.007 / 3.132, T 3.887 / 3.762; 4: 1 sq / 1 x 3/4, S 3.436 / 3.561, T 4.441 / 4.316; 5: 1-1/4 sq / 1-1/4 x 7/8, S 4.296 / 4.483, T 5.551 / 5.363; 6: 1-1/2 sq / 1-1/2 x 1, S 5.155 / 5.405, T 6.660 / 6.410.",
   "An inch parallel key sits half in the shaft keyseat and half in the hub keyseat. ANSI B17.1 gives, for a shaft-diameter range, one key width W, a square height H = W, and a lower rectangular key (height H) that is used on bigger shafts: square keys are preferred up to a 6-1/2 in shaft and rectangular keys for larger ones. The keyseat depth in the shaft (nominal) is H/2. The shaft ranges are 'over x to and including y'; the standard says they identify key sizes and are not meant to set shaft sizes.",
   "Numbers: the ANSI B17.1 shaft-to-key table as reproduced by Engineers Edge and by GlobalSpec (they agree on every row shown), and Engineers Edge's keyseat-depth table (S = shaft depth measured from the opposite side, T = hub depth) for nominal shafts 1-3/4 to 6 in. The generator checks H = W and keyseat depth = H/2 on the key table and, for every S / T row, T - S = key height + 0.005 in for both the square and the rectangular key, which also confirms which key belongs to which shaft range. The footnote that marks the 1-1/2 x 1-1/2 rectangular key on the 6-1/2 to 7-1/2 shaft is not shown (that size is above this page).",
   "Numbers only, no files: a key is a plain bar (a box with no published chamfers), and the length is chosen by the user. Square keys up to 1/2 in wide are on the 'Square keys, inch' page with files; this page adds the larger square keys and all the rectangular ones.",
   "Left out: keys wider than 1-1/2 in, tapered (gib-head) keys, the tolerances on W and H, the S / T values for 1/2 to 1-1/2 in shafts and 7 in and larger (the Engineers Edge table read here starts at 1-3/4), Woodruff keys (their own pages)."
  ],
  "table": {
   "columns": [
    "shaft Ø over to (incl.), in",
    "key width W, in (mm)",
    "square key W x H, in (mm)",
    "rectangular key W x H, in (mm)",
    "keyseat depth H/2, square key, in (mm)",
    "keyseat depth H/2, rectangular key, in (mm)"
   ],
   "rows": [
    [
     "5/16 to 7/16",
     "3/32 (2.381)",
     "3/32 x 3/32 (2.381 x 2.381)",
     "none listed",
     "3/64 (1.191)",
     "—"
    ],
    [
     "7/16 to 9/16",
     "1/8 (3.175)",
     "1/8 x 1/8 (3.175 x 3.175)",
     "1/8 x 3/32 (3.175 x 2.381)",
     "1/16 (1.588)",
     "3/64 (1.191)"
    ],
    [
     "9/16 to 7/8",
     "3/16 (4.763)",
     "3/16 x 3/16 (4.763 x 4.763)",
     "3/16 x 1/8 (4.763 x 3.175)",
     "3/32 (2.381)",
     "1/16 (1.588)"
    ],
    [
     "7/8 to 1-1/4",
     "1/4 (6.35)",
     "1/4 x 1/4 (6.35 x 6.35)",
     "1/4 x 3/16 (6.35 x 4.763)",
     "1/8 (3.175)",
     "3/32 (2.381)"
    ],
    [
     "1-1/4 to 1-3/8",
     "5/16 (7.938)",
     "5/16 x 5/16 (7.938 x 7.938)",
     "5/16 x 1/4 (7.938 x 6.35)",
     "5/32 (3.969)",
     "1/8 (3.175)"
    ],
    [
     "1-3/8 to 1-3/4",
     "3/8 (9.525)",
     "3/8 x 3/8 (9.525 x 9.525)",
     "3/8 x 1/4 (9.525 x 6.35)",
     "3/16 (4.763)",
     "1/8 (3.175)"
    ],
    [
     "1-3/4 to 2-1/4",
     "1/2 (12.7)",
     "1/2 x 1/2 (12.7 x 12.7)",
     "1/2 x 3/8 (12.7 x 9.525)",
     "1/4 (6.35)",
     "3/16 (4.763)"
    ],
    [
     "2-1/4 to 2-3/4",
     "5/8 (15.875)",
     "5/8 x 5/8 (15.875 x 15.875)",
     "5/8 x 7/16 (15.875 x 11.113)",
     "5/16 (7.938)",
     "7/32 (5.556)"
    ],
    [
     "2-3/4 to 3-1/4",
     "3/4 (19.05)",
     "3/4 x 3/4 (19.05 x 19.05)",
     "3/4 x 1/2 (19.05 x 12.7)",
     "3/8 (9.525)",
     "1/4 (6.35)"
    ],
    [
     "3-1/4 to 3-3/4",
     "7/8 (22.225)",
     "7/8 x 7/8 (22.225 x 22.225)",
     "7/8 x 5/8 (22.225 x 15.875)",
     "7/16 (11.113)",
     "5/16 (7.938)"
    ],
    [
     "3-3/4 to 4-1/2",
     "1 (25.4)",
     "1 x 1 (25.4 x 25.4)",
     "1 x 3/4 (25.4 x 19.05)",
     "1/2 (12.7)",
     "3/8 (9.525)"
    ],
    [
     "4-1/2 to 5-1/2",
     "1-1/4 (31.75)",
     "1-1/4 x 1-1/4 (31.75 x 31.75)",
     "1-1/4 x 7/8 (31.75 x 22.225)",
     "5/8 (15.875)",
     "7/16 (11.113)"
    ],
    [
     "5-1/2 to 6-1/2",
     "1-1/2 (38.1)",
     "1-1/2 x 1-1/2 (38.1 x 38.1)",
     "1-1/2 x 1 (38.1 x 25.4)",
     "3/4 (19.05)",
     "1/2 (12.7)"
    ]
   ]
  }
 },
 "sheet_text": "Inch square and rectangular keys to 1-1/2 in (ANSI B17.1): 3/4, 7/8, 1, 1-1/4, 1-1/2 in square, 1/2 x 3/8, 1 x 3/4 in rectangular keys, shaft range and keyseat depth — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/inch-keys-square-rectangular-ansi-b17-1/  (sheet CC BY 4.0)\nBasis: ANSI B17.1 shaft-to-key table (Engineers Edge and GlobalSpec agree) with Engineers Edge keyseat S / T depths cross-checked by T - S = H + 0.005; numbers only\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Keyseat depths in inches from Engineers Edge (nominal shaft: key square / rectangular; S shaft keyseat square and rectangular; T hub keyseat, parallel, square and rectangular): 1-3/4: 3/8 sq / 3/8 x 1/4, S 1.542 / 1.605, T 1.922 / 1.860; 2: 1/2 sq / 1/2 x 3/8, S 1.718 / 1.781, T 2.223 / 2.161; 2-1/4: 1/2 sq / 1/2 x 3/8, S 1.972 / 2.034, T 2.477 / 2.414; 2-1/2: 5/8 sq / 5/8 x 7/16, S 2.148 / 2.242, T 2.778 / 2.684; 3: 3/4 sq / 3/4 x 1/2, S 2.577 / 2.702, T 3.332 / 3.207; 3-1/2: 7/8 sq / 7/8 x 5/8, S 3.007 / 3.132, T 3.887 / 3.762; 4: 1 sq / 1 x 3/4, S 3.436 / 3.561, T 4.441 / 4.316; 5: 1-1/4 sq / 1-1/4 x 7/8, S 4.296 / 4.483, T 5.551 / 5.363; 6: 1-1/2 sq / 1-1/2 x 1, S 5.155 / 5.405, T 6.660 / 6.410.\n- An inch parallel key sits half in the shaft keyseat and half in the hub keyseat. ANSI B17.1 gives, for a shaft-diameter range, one key width W, a square height H = W, and a lower rectangular key (height H) that is used on bigger shafts: square keys are preferred up to a 6-1/2 in shaft and rectangular keys for larger ones. The keyseat depth in the shaft (nominal) is H/2. The shaft ranges are 'over x to and including y'; the standard says they identify key sizes and are not meant to set shaft sizes.\n- Numbers: the ANSI B17.1 shaft-to-key table as reproduced by Engineers Edge and by GlobalSpec (they agree on every row shown), and Engineers Edge's keyseat-depth table (S = shaft depth measured from the opposite side, T = hub depth) for nominal shafts 1-3/4 to 6 in. The generator checks H = W and keyseat depth = H/2 on the key table and, for every S / T row, T - S = key height + 0.005 in for both the square and the rectangular key, which also confirms which key belongs to which shaft range. The footnote that marks the 1-1/2 x 1-1/2 rectangular key on the 6-1/2 to 7-1/2 shaft is not shown (that size is above this page).\n- Numbers only, no files: a key is a plain bar (a box with no published chamfers), and the length is chosen by the user. Square keys up to 1/2 in wide are on the 'Square keys, inch' page with files; this page adds the larger square keys and all the rectangular ones.\n- Left out: keys wider than 1-1/2 in, tapered (gib-head) keys, the tolerances on W and H, the S / T values for 1/2 to 1-1/2 in shafts and 7 in and larger (the Engineers Edge table read here starts at 1-3/4), Woodruff keys (their own pages).\n\nshaft Ø over to (incl.), in  key width W, in (mm)  square key W x H, in (mm)  rectangular key W x H, in (mm)  keyseat depth H/2, square key, in (mm)  keyseat depth H/2, rectangular key, in (mm)\n5/16 to 7/16  3/32 (2.381)  3/32 x 3/32 (2.381 x 2.381)  none listed  3/64 (1.191)  —\n7/16 to 9/16  1/8 (3.175)  1/8 x 1/8 (3.175 x 3.175)  1/8 x 3/32 (3.175 x 2.381)  1/16 (1.588)  3/64 (1.191)\n9/16 to 7/8  3/16 (4.763)  3/16 x 3/16 (4.763 x 4.763)  3/16 x 1/8 (4.763 x 3.175)  3/32 (2.381)  1/16 (1.588)\n7/8 to 1-1/4  1/4 (6.35)  1/4 x 1/4 (6.35 x 6.35)  1/4 x 3/16 (6.35 x 4.763)  1/8 (3.175)  3/32 (2.381)\n1-1/4 to 1-3/8  5/16 (7.938)  5/16 x 5/16 (7.938 x 7.938)  5/16 x 1/4 (7.938 x 6.35)  5/32 (3.969)  1/8 (3.175)\n1-3/8 to 1-3/4  3/8 (9.525)  3/8 x 3/8 (9.525 x 9.525)  3/8 x 1/4 (9.525 x 6.35)  3/16 (4.763)  1/8 (3.175)\n1-3/4 to 2-1/4  1/2 (12.7)  1/2 x 1/2 (12.7 x 12.7)  1/2 x 3/8 (12.7 x 9.525)  1/4 (6.35)  3/16 (4.763)\n2-1/4 to 2-3/4  5/8 (15.875)  5/8 x 5/8 (15.875 x 15.875)  5/8 x 7/16 (15.875 x 11.113)  5/16 (7.938)  7/32 (5.556)\n2-3/4 to 3-1/4  3/4 (19.05)  3/4 x 3/4 (19.05 x 19.05)  3/4 x 1/2 (19.05 x 12.7)  3/8 (9.525)  1/4 (6.35)\n3-1/4 to 3-3/4  7/8 (22.225)  7/8 x 7/8 (22.225 x 22.225)  7/8 x 5/8 (22.225 x 15.875)  7/16 (11.113)  5/16 (7.938)\n3-3/4 to 4-1/2  1 (25.4)  1 x 1 (25.4 x 25.4)  1 x 3/4 (25.4 x 19.05)  1/2 (12.7)  3/8 (9.525)\n4-1/2 to 5-1/2  1-1/4 (31.75)  1-1/4 x 1-1/4 (31.75 x 31.75)  1-1/4 x 7/8 (31.75 x 22.225)  5/8 (15.875)  7/16 (11.113)\n5-1/2 to 6-1/2  1-1/2 (38.1)  1-1/2 x 1-1/2 (38.1 x 38.1)  1-1/2 x 1 (38.1 x 25.4)  3/4 (19.05)  1/2 (12.7)\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Engineers Edge: Shaft diameter vs key sizes (ANSI B17.1): W, square H, rectangular H, keyseat depth H/2 — web — Publisher's page; dimensions are facts — https://engineersedge.com/gears/shaft_diameter_vs_key_sizes_14411.htm\n- GlobalSpec (ANSI B17.1-1967 R1998 excerpt): Keys and keyseats: shaft diameter, key width W, height H square and rectangular, keyseat depth H/2 — web — Publisher's page; dimensions are facts — https://www.globalspec.com/reference/77011/203279/keys-and-keyseats\n- Engineers Edge: Shaft and hub keyseat depth S and T for square and rectangular keys (ANSI B17.1), 1-3/4 to 7 in shafts — web — Publisher's page; dimensions are facts — https://engineersedge.com/gears/shaft_key_seat_depth_14412.htm\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=inch-keys-square-rectangular-ansi-b17-1\n",
 "sources": [
  {
   "publisher": "Engineers Edge",
   "title": "Shaft diameter vs key sizes (ANSI B17.1): W, square H, rectangular H, keyseat depth H/2",
   "url": "https://engineersedge.com/gears/shaft_diameter_vs_key_sizes_14411.htm",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "GlobalSpec (ANSI B17.1-1967 R1998 excerpt)",
   "title": "Keys and keyseats: shaft diameter, key width W, height H square and rectangular, keyseat depth H/2",
   "url": "https://www.globalspec.com/reference/77011/203279/keys-and-keyseats",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Engineers Edge",
   "title": "Shaft and hub keyseat depth S and T for square and rectangular keys (ANSI B17.1), 1-3/4 to 7 in shafts",
   "url": "https://engineersedge.com/gears/shaft_key_seat_depth_14412.htm",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "not-scanned",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "square-keys-inch",
  "parallel-keys-din-6885",
  "woodruff-keys-inch-ansi-b17-2",
  "woodruff-keys-din-6888",
  "hex-keys-iso-2936-asme-b18-3"
 ],
 "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": "What key goes on a 2 in shaft?",
   "a": "A 1/2 in square key (the 1-3/4 to 2-1/4 in shaft range); the rectangular key is 1/2 wide by 3/8 high. Shaft keyseat depth about H/2 = 1/4 in."
  },
  {
   "q": "What key goes on a 3 in shaft?",
   "a": "A 3/4 in square key (shaft range 2-3/4 to 3-1/4); the rectangular key is 3/4 x 1/2."
  },
  {
   "q": "What key goes on a 4 in shaft?",
   "a": "A 1 in square key (3-3/4 to 4-1/2 range); rectangular 1 x 3/4."
  },
  {
   "q": "What is the keyseat depth for a square key?",
   "a": "H/2, i.e. half the key height: 1/4 in for a 1/2 in square key, 1/2 in for a 1 in square key."
  },
  {
   "q": "When are rectangular keys used?",
   "a": "ANSI B17.1 prefers square keys up to a 6-1/2 in shaft and rectangular keys above that; the rectangular keys are also listed for smaller shafts, with a lower height, where the shaft cannot take the deeper keyseat."
  }
 ],
 "files_license": null,
 "offers": [],
 "markdown": "https://xemstudio.com/objects/inch-keys-square-rectangular-ansi-b17-1/index.md"
}