{
 "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": "iso-k-iso-f-flanges-dn63-dn630",
 "name": "ISO-K and ISO-F large vacuum flanges (ISO 1609): OD, bolt circle, hole count and diameter, centering ring lip, DN63 to DN630, + ISO-F bolt-pattern templates",
 "kind": "standard",
 "category": "Hardware",
 "group": "Vacuum flanges",
 "year": null,
 "question": "What are the bolt circle, hole count and OD of an ISO-F (LF) vacuum flange DN100, DN160, DN250?",
 "tags": [
  "iso-k",
  "iso-f",
  "lf flange",
  "large flange",
  "vacuum flange",
  "iso 1609",
  "bolt circle",
  "centering ring",
  "vacuum",
  "tool"
 ],
 "aliases": [
  "iso-f flange dimensions",
  "iso 100 flange bolt circle",
  "iso-k flange od",
  "lf100 flange dimensions",
  "iso 160 flange bolt pattern",
  "iso 63 flange",
  "iso 1609",
  "iso large flange sizes",
  "iso-f 250 bolt circle",
  "dn100 iso-k dimensions",
  "iso f vs iso k"
 ],
 "overall_mm": {
  "length": 750,
  "width": 750,
  "height": 6
 },
 "official_cad": false,
 "xem_status": "not-scanned",
 "les": false,
 "free_files": 0,
 "url": "https://xemstudio.com/objects/iso-k-iso-f-flanges-dn63-dn630/",
 "sheet_txt": "https://xemstudio.com/objects/iso-k-iso-f-flanges-dn63-dn630/sheet.txt",
 "sheet": {
  "basis": "Kurt J. Lesker's ISO tables as reproduced in Cornell CLASSE technical notes, cross-checked against the sample pages of ISO 1609:1986; numbers for ISO-K and the centering ring, bolt-pattern templates for ISO-F as files",
  "overall_mm": {
   "length": 750,
   "width": 750,
   "height": 6
  },
  "notes": [
   "ISO-K and ISO-F (also LF, 'large flange', or ISO 1609) are the large vacuum flanges: ISO-K flanges are joined with clamps and ISO-F flanges with bolts through holes on a bolt circle. Both use a centering ring with an O-ring. Sizes are named by nominal bore in mm: 63, 80, 100, 160, 200, 250, 320, 400, 500, 630.",
   "All values mm. ISO-F: flange OD, number of holes, hole diameter and bolt circle (BCD) are from the Lesker table (inches there, given with mm: 130 / 145 / 165 / 225 / 285 / 335 / 425 / 510 / 610 / 750 mm OD; BCD 110 / 125 / 145 / 200 / 260 / 310 / 395 / 480 / 580 / 720 mm; holes 4, 8, 8, 8, 12, 12, 12, 16, 16, 20; hole Ø 9, 9, 9, 11, 11, 11, 14, 14, 14, 14 mm; bolts M8 to M12 as printed '5/16 (M8)', '3/8 (M10)', '1/2 (M12)'). ISO-K flange OD is 95, 110, 130, 180, 240, 290, 370, 450, 550, 690 mm.",
   "Cross-check against the standard: the OCR'd sample of ISO 1609:1986 (bolted flanges, nominal bore 200 to 1000, headers partly unreadable) repeats the same numbers for 200 to 630: 285 / 335 / 425 / 510 / 610 / 750 (outside diameter), 260 / 310 / 395 / 480 / 580 / 720 (bolt circle), 12 / 12 / 12 / 16 / 16 / 20 (holes), 240 / 290 / 370 / 450 / 550 / 690 (K flange OD) and 213 / 261 / 318 / 400 / 501 / 651 (centering ring lip OD). The sample's other columns (c, Y, D, M) cannot be assigned from the garbled headers and are not used, so hole diameter and bolt size above are Lesker's only.",
   "Centering ring lip OD and ID (Lesker, mm): the lip OD fits the flange recess. ISO 1609 also gives 800 and 1000 bolted flanges and recommends 1250 to 2500; these are not on the Lesker table read and are not covered here.",
   "Files: ISO-F bolt-pattern templates, one per size: a disc of the flange OD with the published hole count, hole diameter and bolt circle. Thickness (6 mm), the central aperture (half the bolt circle) and the position of the first hole (on +X) are Xem choices; the hole orientation relative to the sealing axis is not given by the sources. The collar, recess and sealing face are not modelled (no published numbers read). ISO-K clamp flanges are not drawn: their clamp seat is not dimensioned in the sources read.",
   "Small flanges are on iso-kf-flanges-nw10-nw50 and knife-edge flanges on conflat-cf-flanges. McMaster-Carr's vacuum-fittings category is linked for per-part STEP."
  ],
  "table": {
   "columns": [
    "size",
    "ISO-K flange OD",
    "ISO-F flange OD",
    "ISO-F bolt circle",
    "ISO-F holes",
    "hole Ø",
    "bolt",
    "centering ring lip OD",
    "lip ID"
   ],
   "rows": [
    [
     "DN63",
     95,
     130,
     110,
     4,
     9,
     "M8 (bolt 5/16 in)",
     70,
     66.8
    ],
    [
     "DN80",
     110,
     145,
     125,
     8,
     9,
     "M8 (bolt 5/16 in)",
     83,
     79.8
    ],
    [
     "DN100",
     130,
     165,
     145,
     8,
     9,
     "M8 (bolt 5/16 in)",
     102,
     98.8
    ],
    [
     "DN160",
     180,
     225,
     200,
     8,
     11,
     "M10 (bolt 3/8 in)",
     153,
     149.9
    ],
    [
     "DN200",
     240,
     285,
     260,
     12,
     11,
     "M10 (bolt 3/8 in)",
     213,
     209.8
    ],
    [
     "DN250",
     290,
     335,
     310,
     12,
     11,
     "M10 (bolt 3/8 in)",
     261,
     257.6
    ],
    [
     "DN320",
     370,
     425,
     395,
     12,
     14,
     "M12 (bolt 1/2 in)",
     318,
     312.4
    ],
    [
     "DN400",
     450,
     510,
     480,
     16,
     14,
     "M12 (bolt 1/2 in)",
     400,
     394.5
    ],
    [
     "DN500",
     550,
     610,
     580,
     16,
     14,
     "M12 (bolt 1/2 in)",
     501,
     495.6
    ],
    [
     "DN630",
     690,
     750,
     720,
     20,
     14,
     "M12 (bolt 1/2 in)",
     651,
     645.4
    ]
   ]
  }
 },
 "sheet_text": "ISO-K and ISO-F large vacuum flanges (ISO 1609): OD, bolt circle, hole count and diameter, centering ring lip, DN63 to DN630, + ISO-F bolt-pattern templates — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/iso-k-iso-f-flanges-dn63-dn630/  (sheet CC BY 4.0)\nBasis: Kurt J. Lesker's ISO tables as reproduced in Cornell CLASSE technical notes, cross-checked against the sample pages of ISO 1609:1986; numbers for ISO-K and the centering ring, bolt-pattern templates for ISO-F as files\nCatalog version: 2026-10-20\n\nOverall (mm): length 750.0, width 750.0, height 6.0\n- ISO-K and ISO-F (also LF, 'large flange', or ISO 1609) are the large vacuum flanges: ISO-K flanges are joined with clamps and ISO-F flanges with bolts through holes on a bolt circle. Both use a centering ring with an O-ring. Sizes are named by nominal bore in mm: 63, 80, 100, 160, 200, 250, 320, 400, 500, 630.\n- All values mm. ISO-F: flange OD, number of holes, hole diameter and bolt circle (BCD) are from the Lesker table (inches there, given with mm: 130 / 145 / 165 / 225 / 285 / 335 / 425 / 510 / 610 / 750 mm OD; BCD 110 / 125 / 145 / 200 / 260 / 310 / 395 / 480 / 580 / 720 mm; holes 4, 8, 8, 8, 12, 12, 12, 16, 16, 20; hole Ø 9, 9, 9, 11, 11, 11, 14, 14, 14, 14 mm; bolts M8 to M12 as printed '5/16 (M8)', '3/8 (M10)', '1/2 (M12)'). ISO-K flange OD is 95, 110, 130, 180, 240, 290, 370, 450, 550, 690 mm.\n- Cross-check against the standard: the OCR'd sample of ISO 1609:1986 (bolted flanges, nominal bore 200 to 1000, headers partly unreadable) repeats the same numbers for 200 to 630: 285 / 335 / 425 / 510 / 610 / 750 (outside diameter), 260 / 310 / 395 / 480 / 580 / 720 (bolt circle), 12 / 12 / 12 / 16 / 16 / 20 (holes), 240 / 290 / 370 / 450 / 550 / 690 (K flange OD) and 213 / 261 / 318 / 400 / 501 / 651 (centering ring lip OD). The sample's other columns (c, Y, D, M) cannot be assigned from the garbled headers and are not used, so hole diameter and bolt size above are Lesker's only.\n- Centering ring lip OD and ID (Lesker, mm): the lip OD fits the flange recess. ISO 1609 also gives 800 and 1000 bolted flanges and recommends 1250 to 2500; these are not on the Lesker table read and are not covered here.\n- Files: ISO-F bolt-pattern templates, one per size: a disc of the flange OD with the published hole count, hole diameter and bolt circle. Thickness (6 mm), the central aperture (half the bolt circle) and the position of the first hole (on +X) are Xem choices; the hole orientation relative to the sealing axis is not given by the sources. The collar, recess and sealing face are not modelled (no published numbers read). ISO-K clamp flanges are not drawn: their clamp seat is not dimensioned in the sources read.\n- Small flanges are on iso-kf-flanges-nw10-nw50 and knife-edge flanges on conflat-cf-flanges. McMaster-Carr's vacuum-fittings category is linked for per-part STEP.\n\nsize  ISO-K flange OD  ISO-F flange OD  ISO-F bolt circle  ISO-F holes  hole Ø  bolt  centering ring lip OD  lip ID\nDN63  95  130  110  4  9  M8 (bolt 5/16 in)  70  66.8\nDN80  110  145  125  8  9  M8 (bolt 5/16 in)  83  79.8\nDN100  130  165  145  8  9  M8 (bolt 5/16 in)  102  98.8\nDN160  180  225  200  8  11  M10 (bolt 3/8 in)  153  149.9\nDN200  240  285  260  12  11  M10 (bolt 3/8 in)  213  209.8\nDN250  290  335  310  12  11  M10 (bolt 3/8 in)  261  257.6\nDN320  370  425  395  12  14  M12 (bolt 1/2 in)  318  312.4\nDN400  450  510  480  16  14  M12 (bolt 1/2 in)  400  394.5\nDN500  550  610  580  16  14  M12 (bolt 1/2 in)  501  495.6\nDN630  690  750  720  20  14  M12 (bolt 1/2 in)  651  645.4\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Cornell CLASSE (technical notes, reproducing Kurt J. Lesker ISO tables): ISO flanges technical notes: ISO-F flange OD, holes, bolt circle, bolts; ISO-K flange OD; centering ring lip OD and ID, sizes 63 to 630 — web — Lab technical notes; numbers only — https://www.classe.cornell.edu/~dms79/D-lineNotes/components/ISO%20Flanges-TechnicalNotes.htm\n- ISO (iTeh preview): ISO 1609:1986 Vacuum technology - Flange dimensions (sample pages, OCR with garbled headers): bolted flange rows for nominal bores 200 to 1000 — web — Standard preview; numbers only; headers partly unreadable — https://cdn.standards.iteh.ai/samples/6209/2492d409536f44d6865afcbaaf717433/ISO-1609-1986.pdf\n- ANCORP (catalogue): ISO quick flange (QF/KF) and large flange (LF) centering rings: ID cross-reference, A and B dimensions in inches (stainless and aluminium centering ring assemblies) — web — Maker catalogue; numbers only — https://future4200.com/uploads/short-url/aRKA89A8sSu693NTJW9PFqCukFa.pdf\n- Kurt J. Lesker (catalogue, extracted text): Flanges, fittings and components: CF fixed flange standard dimensions (bolts, hole diameter, tapped thread, bolt circle); size lists for KF 1-4 and ISO 1-5 — web — Maker catalogue copy; numbers only. Column letters were not labelled in the extracted text — https://www.acomee.com.mx/catalogos/catalogosk/KURT-J-LESKER FLANGES, FITTINGS AND COMPONENTS.pdf\n- McMaster-Carr: Vacuum fittings (KF / ISO flanges) (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/vacuum-fittings/\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=iso-k-iso-f-flanges-dn63-dn630\n",
 "sources": [
  {
   "publisher": "Cornell CLASSE (technical notes, reproducing Kurt J. Lesker ISO tables)",
   "title": "ISO flanges technical notes: ISO-F flange OD, holes, bolt circle, bolts; ISO-K flange OD; centering ring lip OD and ID, sizes 63 to 630",
   "url": "https://www.classe.cornell.edu/~dms79/D-lineNotes/components/ISO%20Flanges-TechnicalNotes.htm",
   "formats": [
    "web"
   ],
   "license": "Lab technical notes; numbers only",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "ISO (iTeh preview)",
   "title": "ISO 1609:1986 Vacuum technology - Flange dimensions (sample pages, OCR with garbled headers): bolted flange rows for nominal bores 200 to 1000",
   "url": "https://cdn.standards.iteh.ai/samples/6209/2492d409536f44d6865afcbaaf717433/ISO-1609-1986.pdf",
   "formats": [
    "web"
   ],
   "license": "Standard preview; numbers only; headers partly unreadable",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "ANCORP (catalogue)",
   "title": "ISO quick flange (QF/KF) and large flange (LF) centering rings: ID cross-reference, A and B dimensions in inches (stainless and aluminium centering ring assemblies)",
   "url": "https://future4200.com/uploads/short-url/aRKA89A8sSu693NTJW9PFqCukFa.pdf",
   "formats": [
    "web"
   ],
   "license": "Maker catalogue; numbers only",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Kurt J. Lesker (catalogue, extracted text)",
   "title": "Flanges, fittings and components: CF fixed flange standard dimensions (bolts, hole diameter, tapped thread, bolt circle); size lists for KF 1-4 and ISO 1-5",
   "url": "https://www.acomee.com.mx/catalogos/catalogosk/KURT-J-LESKER FLANGES, FITTINGS AND COMPONENTS.pdf",
   "formats": [
    "web"
   ],
   "license": "Maker catalogue copy; numbers only. Column letters were not labelled in the extracted text",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "McMaster-Carr",
   "title": "Vacuum fittings (KF / ISO flanges) (free STEP/IGES per part, for your own design use; no redistribution)",
   "url": "https://www.mcmaster.com/products/vacuum-fittings/",
   "formats": [
    "STEP",
    "IGES",
    "PDF"
   ],
   "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": [
  "iso-kf-flanges-nw10-nw50",
  "conflat-cf-flanges",
  "asme-b16-5-class-150-flanges",
  "asme-b16-5-flange-bolt-patterns",
  "camlock-couplings",
  "metabo-vacuum-hose-sizes"
 ],
 "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": "ISO-F bolt holes",
   "exact": "DN63: 4 × Ø9 on Ø110; DN80: 8 × Ø9 on Ø125; DN100: 8 × Ø9 on Ø145; DN160: 8 × Ø11 on Ø200; DN200 / 250: 12 × Ø11 on Ø260 / Ø310; DN320: 12 × Ø14 on Ø395; DN400 / 500: 16 × Ø14 on Ø480 / Ø580; DN630: 20 × Ø14 on Ø720",
   "mates": "M8 (DN63-100), M10 (DN160-250) or M12 (DN320-630) bolts through the mating ISO-F flange's identical pattern (Lesker table)",
   "fit": "slide",
   "files": "iso-f-bolt-pattern"
  },
  {
   "feature": "centering ring lip OD",
   "exact": "Ø70 (DN63), 83, 102, 153, 213, 261, 318, 400, 501, Ø651 (DN630) (Lesker; ISO 1609 sample repeats 213 to 651)",
   "mates": "flange recess that locates the centering ring with its O-ring",
   "fit": "slide",
   "files": "all"
  }
 ],
 "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 is the bolt circle of an ISO-F DN100 flange?",
   "a": "145 mm: 8 holes of Ø9 for M8 bolts, flange OD 165 mm."
  },
  {
   "q": "What is the OD of an ISO-K DN160 flange?",
   "a": "180 mm (the ISO-F DN160 flange is 225 mm OD, 8 × Ø11 holes on a 200 mm bolt circle)."
  },
  {
   "q": "What is the difference between ISO-K and ISO-F?",
   "a": "ISO-K is clamped over a tapered back; ISO-F is bolted through holes on a bolt circle. Both seal with a centering ring."
  }
 ],
 "files_license": null,
 "offers": [],
 "markdown": "https://xemstudio.com/objects/iso-k-iso-f-flanges-dn63-dn630/index.md"
}