{
 "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": "caster-stems-threaded-grip-ring",
 "name": "Caster stem types and sizes: threaded stem (3/8-16, 1/2-13, M10, M12), grip ring 7/16 in, expanding adapter, bolt-hole fitting",
 "kind": "standard",
 "category": "Hardware",
 "group": "Casters & wheels",
 "year": null,
 "question": "What stem sizes do stem casters come in: 3/8-16, 1/2-13, M10, M12, grip ring 7/16 in?",
 "tags": [
  "caster",
  "stem caster",
  "threaded stem",
  "grip ring",
  "stem",
  "expanding stem",
  "castor"
 ],
 "aliases": [
  "stem caster sizes",
  "threaded stem caster 1/2-13",
  "3/8-16 stem caster",
  "m12 stem caster",
  "grip ring stem caster 7/16",
  "friction ring stem",
  "expanding stem caster tube size",
  "caster stem length",
  "castor stem types",
  "m10 threaded stem castor"
 ],
 "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/caster-stems-threaded-grip-ring/",
 "sheet_txt": "https://xemstudio.com/objects/caster-stems-threaded-grip-ring/sheet.txt",
 "sheet": {
  "basis": "One retailer's stem-caster sizing guide (text and spec sheet) and a Blickle bolt-hole datasheet, read in this session; numbers only",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A stem caster is held to the equipment by a stem instead of a top plate: a threaded stem screws into a tapped hole or nut, a grip-ring stem presses into a socket, an expanding adapter wedges in a tube. Thread sizes the guide lists: UNC 3/8-16, 1/2-13, 5/8-11, 3/4-10, 1-8; UNF 3/8-24, 1/2-20, 5/8-18; metric M8, M10, M12, M16 (BSF / BSW are mentioned without sizes). Stem lengths are measured from the caster plate or shoulder to the tip.",
   "Stem diameters printed: 1/4 (.250), 5/16 (.313), 3/8 (.375), 7/16 (.437, grip ring), 1/2 (.500), 5/8 (.625), 3/4 (.750), 7/8 (.875), 1 (1.000) in. The guide says the stem diameter must match the host hole or tube within 1/64 in. It prints no tap-drill, host-hole or socket diameters, so none is given here.",
   "Grip ring: the guide's table lists 7/16 × 7/8 and 7/16 × 1-7/16 in; its introduction says 7/16 and 1/2 in diameters exist, but 1/2 in is not in its size table. A commonly quoted '7/16 × 1-3/8' size is not on this guide and is not used.",
   "No file: the shape of a stem fitting (collar, shoulder, grip ring, kingpin) is not defined by published numbers in the sources read. Plate casters are on caster-top-plate-patterns."
  ],
  "table": {
   "columns": [
    "stem type",
    "thread / diameter (inch)",
    "UNF (fine)",
    "metric",
    "length",
    "host"
   ],
   "rows": [
    [
     "threaded stem",
     "UNC 3/8-16, 1/2-13, 5/8-11, 3/4-10, 1-8",
     "UNF 3/8-24, 1/2-20, 5/8-18",
     "M8, M10, M12, M16",
     "1, 1-1/2, 1-3/4, 2 in (from the plate to the tip)",
     "tapped hole in the host; no tap drill printed"
    ],
    [
     "grip ring (friction ring) stem",
     "7/16 in diameter (the guide's table; its text also mentions 1/2 in)",
     "—",
     "—",
     "7/8 in or 1-7/16 in; sizes printed 7/16 × 7/8 and 7/16 × 1-7/16",
     "precision-fit socket; no socket size printed"
    ],
    [
     "expanding adapter stem",
     "—",
     "—",
     "—",
     "1-1/2 to 2 in compressed",
     "tube ID between the compressed and expanded OD; tube sizes 7/8, 1, 1-1/8, 1-1/4 in (and metric)"
    ],
    [
     "plain round stem and square stem",
     "—",
     "—",
     "—",
     "varies by OEM",
     "—"
    ],
    [
     "bolt-hole fitting (not a stem)",
     "—",
     "—",
     "Blickle LMDA-TPA 50 and 75: hole Ø10.2 mm, plate Ø41 / Ø55 mm",
     "—",
     "single central bolt"
    ]
   ]
  }
 },
 "sheet_text": "Caster stem types and sizes: threaded stem (3/8-16, 1/2-13, M10, M12), grip ring 7/16 in, expanding adapter, bolt-hole fitting — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/caster-stems-threaded-grip-ring/  (sheet CC BY 4.0)\nBasis: One retailer's stem-caster sizing guide (text and spec sheet) and a Blickle bolt-hole datasheet, read in this session; numbers only\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A stem caster is held to the equipment by a stem instead of a top plate: a threaded stem screws into a tapped hole or nut, a grip-ring stem presses into a socket, an expanding adapter wedges in a tube. Thread sizes the guide lists: UNC 3/8-16, 1/2-13, 5/8-11, 3/4-10, 1-8; UNF 3/8-24, 1/2-20, 5/8-18; metric M8, M10, M12, M16 (BSF / BSW are mentioned without sizes). Stem lengths are measured from the caster plate or shoulder to the tip.\n- Stem diameters printed: 1/4 (.250), 5/16 (.313), 3/8 (.375), 7/16 (.437, grip ring), 1/2 (.500), 5/8 (.625), 3/4 (.750), 7/8 (.875), 1 (1.000) in. The guide says the stem diameter must match the host hole or tube within 1/64 in. It prints no tap-drill, host-hole or socket diameters, so none is given here.\n- Grip ring: the guide's table lists 7/16 × 7/8 and 7/16 × 1-7/16 in; its introduction says 7/16 and 1/2 in diameters exist, but 1/2 in is not in its size table. A commonly quoted '7/16 × 1-3/8' size is not on this guide and is not used.\n- No file: the shape of a stem fitting (collar, shoulder, grip ring, kingpin) is not defined by published numbers in the sources read. Plate casters are on caster-top-plate-patterns.\n\nstem type  thread / diameter (inch)  UNF (fine)  metric  length  host\nthreaded stem  UNC 3/8-16, 1/2-13, 5/8-11, 3/4-10, 1-8  UNF 3/8-24, 1/2-20, 5/8-18  M8, M10, M12, M16  1, 1-1/2, 1-3/4, 2 in (from the plate to the tip)  tapped hole in the host; no tap drill printed\ngrip ring (friction ring) stem  7/16 in diameter (the guide's table; its text also mentions 1/2 in)  —  —  7/8 in or 1-7/16 in; sizes printed 7/16 × 7/8 and 7/16 × 1-7/16  precision-fit socket; no socket size printed\nexpanding adapter stem  —  —  —  1-1/2 to 2 in compressed  tube ID between the compressed and expanded OD; tube sizes 7/8, 1, 1-1/8, 1-1/4 in (and metric)\nplain round stem and square stem  —  —  —  varies by OEM  —\nbolt-hole fitting (not a stem)  —  —  Blickle LMDA-TPA 50 and 75: hole Ø10.2 mm, plate Ø41 / Ø55 mm  —  single central bolt\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- CasterHQ: Stem casters sizing guide: stem types, thread sizes, stem lengths, grip ring 7/16 in, expanding adapter tube sizes — web — Retailer guide; numbers only — https://casterhq.com/blogs/caster-university/stem-casters-sizing-guide\n- CasterHQ: Stem casters sizing guide spec sheet (PDF) — web — Publisher's page; dimensions are facts — https://casterhq.com/downloads/stem-casters-sizing-guide-spec-sheet\n- Blickle (via Raptor Supplies datasheet): LMDA-TPA 50 / 75 castors with central bolt-hole fitting: wheel diameter, total height, plate diameter, bolt hole diameter, offset — web — Maker datasheet; numbers only — https://static.raptorsupplies.com/catalog/product/datasheet/blickle-lmda-tpa-50k-fk.pdf\n- McMaster-Carr: Casters (plate, stem, bolt-hole) (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/casters/\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=caster-stems-threaded-grip-ring\n",
 "sources": [
  {
   "publisher": "CasterHQ",
   "title": "Stem casters sizing guide: stem types, thread sizes, stem lengths, grip ring 7/16 in, expanding adapter tube sizes",
   "url": "https://casterhq.com/blogs/caster-university/stem-casters-sizing-guide",
   "formats": [
    "web"
   ],
   "license": "Retailer guide; numbers only",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "CasterHQ",
   "title": "Stem casters sizing guide spec sheet (PDF)",
   "url": "https://casterhq.com/downloads/stem-casters-sizing-guide-spec-sheet",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Blickle (via Raptor Supplies datasheet)",
   "title": "LMDA-TPA 50 / 75 castors with central bolt-hole fitting: wheel diameter, total height, plate diameter, bolt hole diameter, offset",
   "url": "https://static.raptorsupplies.com/catalog/product/datasheet/blickle-lmda-tpa-50k-fk.pdf",
   "formats": [
    "web"
   ],
   "license": "Maker datasheet; numbers only",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "McMaster-Carr",
   "title": "Casters (plate, stem, bolt-hole) (free STEP/IGES per part, for your own design use; no redistribution)",
   "url": "https://www.mcmaster.com/products/casters/",
   "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": [
  "caster-top-plate-patterns",
  "leveling-feet-gn-343-and-mcmaster",
  "t-slot-feet",
  "socket-head-cap-screws-metric",
  "hand-truck-wheels-8-and-10-in"
 ],
 "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": "threaded stem",
   "exact": "UNC 3/8-16, 1/2-13, 5/8-11, 3/4-10, 1-8; UNF 3/8-24, 1/2-20, 5/8-18; M8, M10, M12, M16",
   "mates": "tapped hole or nut of the same thread in the equipment",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "grip ring stem",
   "exact": "Ø7/16 in (11.1 mm) × 7/8 or 1-7/16 in long",
   "mates": "socket within 1/64 in of the stem diameter (guide's rule; socket size not printed)",
   "fit": "press",
   "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 thread is a 1/2 in threaded stem caster?",
   "a": "1/2-13 UNC is the coarse size listed; 1/2-20 UNF is also listed."
  },
  {
   "q": "What size is a grip ring stem caster?",
   "a": "7/16 in diameter, 7/8 in or 1-7/16 in long, on the guide read."
  },
  {
   "q": "What stem lengths are common for threaded stems?",
   "a": "1, 1-1/2, 1-3/4 and 2 in, measured from the top plate to the stem tip."
  }
 ],
 "files_license": null,
 "offers": [],
 "markdown": "https://xemstudio.com/objects/caster-stems-threaded-grip-ring/index.md"
}