{
 "version": "2026-10-20",
 "license": "Dimension sheets are written by Xem Studio from the cited sources and are free to use (CC BY 4.0, attribute 'Xem Studio'). Linked files belong to their publishers under the license shown; Xem Studio does not host them. 'license_verified: false' means the license shown is from memory or the publisher's page as last read and should be confirmed at the link before commercial use.",
 "slug": "drop-in-t-nuts",
 "name": "Drop-in T-nuts for 20, 30, 40 and 10-series (1 in) extrusion",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Framing",
 "year": null,
 "question": "What are drop-in T-nut dimensions for 2020 extrusion?",
 "tags": [
  "t-nut",
  "drop-in",
  "extrusion",
  "2020",
  "t-slot",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "drop in t nut 2020",
  "drop in t nut dimensions",
  "roll in t nut",
  "twist t nut stl",
  "t nut insert from face"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 10,
 "url": "https://xemstudio.com/objects/drop-in-t-nuts/",
 "sheet_txt": "https://xemstudio.com/objects/drop-in-t-nuts/sheet.txt",
 "sheet": {
  "basis": "Drop-in nut: width = slot opening so it passes the opening, length = cavity − 1 so it turns 90° (designed), tap-drill thread hole",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "The nut is as wide as the slot opening, so it drops in through the face, and 1 mm shorter than the cavity width, so it turns 90° to lock behind the lips (designed).",
   "20-series: 10 × 6 × 4.2 body with a 6 × 6 × 1.8 boss, M3 / M4 / M5. 30-series: 15.5 × 8 × 6, boss 8 × 8 × 2.5, M5 / M6 / M8. 40-series: 19 × 8 × 6.5, boss 8 × 8 × 3, M6 / M8. 10-series: 13.4 × 6.5 × 4.8, boss 6.5 × 6.5 × 2.3, 1/4-20 / 10-32.",
   "Thread holes are the standard tap drills (M3 2.5, M4 3.3, M5 4.2, M6 5.0, M8 6.8, 1/4-20 5.1, 10-32 4.0); body edges carry a 1.2 mm chamfer.",
   "Use a drop-in nut where the profile end is already closed."
  ],
  "table": {
   "columns": [
    "series",
    "body_mm",
    "boss_mm",
    "threads"
   ],
   "rows": [
    [
     "20",
     "10 × 6 × 4.2",
     "6 × 6 × 1.8",
     "M3, M4, M5"
    ],
    [
     "30",
     "15.5 × 8 × 6",
     "8 × 8 × 2.5",
     "M5, M6, M8"
    ],
    [
     "40",
     "19 × 8 × 6.5",
     "8 × 8 × 3",
     "M6, M8"
    ],
    [
     "10 (1 in)",
     "13.4 × 6.5 × 4.8",
     "6.5 × 6.5 × 2.3",
     "1/4-20, 10-32"
    ]
   ]
  }
 },
 "sheet_text": "Drop-in T-nuts for 20, 30, 40 and 10-series (1 in) extrusion — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/drop-in-t-nuts/  (CC BY 4.0)\nBasis: Drop-in nut: width = slot opening so it passes the opening, length = cavity − 1 so it turns 90° (designed), tap-drill thread hole\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The nut is as wide as the slot opening, so it drops in through the face, and 1 mm shorter than the cavity width, so it turns 90° to lock behind the lips (designed).\n- 20-series: 10 × 6 × 4.2 body with a 6 × 6 × 1.8 boss, M3 / M4 / M5. 30-series: 15.5 × 8 × 6, boss 8 × 8 × 2.5, M5 / M6 / M8. 40-series: 19 × 8 × 6.5, boss 8 × 8 × 3, M6 / M8. 10-series: 13.4 × 6.5 × 4.8, boss 6.5 × 6.5 × 2.3, 1/4-20 / 10-32.\n- Thread holes are the standard tap drills (M3 2.5, M4 3.3, M5 4.2, M6 5.0, M8 6.8, 1/4-20 5.1, 10-32 4.0); body edges carry a 1.2 mm chamfer.\n- Use a drop-in nut where the profile end is already closed.\n\nseries  body_mm  boss_mm  threads\n20  10 × 6 × 4.2  6 × 6 × 1.8  M3, M4, M5\n30  15.5 × 8 × 6  8 × 8 × 2.5  M5, M6, M8\n40  19 × 8 × 6.5  8 × 8 × 3  M6, M8\n10 (1 in)  13.4 × 6.5 × 4.8  6.5 × 6.5 × 2.3  1/4-20, 10-32\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wikipedia: T-slot nut — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/T-slot_nut\n- OpenBuilds: Tee nuts and brackets for V-slot — web, STEP — OpenBuilds site [verify license at link] — https://openbuildspartstore.com/\n- Long Earth Society: Engine and rig builds on extrusion frames — web, video — LES site — https://longearthsociety.com/engineering/\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 10 parts): https://xemstudio.com/files/hardware/drop-in-t-nuts/index.json\nAPI: https://xemstudio.com/api/geometry?object=drop-in-t-nuts\n",
 "sources": [
  {
   "publisher": "Wikipedia",
   "title": "T-slot nut",
   "url": "https://en.wikipedia.org/wiki/T-slot_nut",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "OpenBuilds",
   "title": "Tee nuts and brackets for V-slot",
   "url": "https://openbuildspartstore.com/",
   "formats": [
    "web",
    "STEP"
   ],
   "license": "OpenBuilds site",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Engine and rig builds on extrusion frames",
   "url": "https://longearthsociety.com/engineering/",
   "formats": [
    "web",
    "video"
   ],
   "license": "LES site",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "slide-in-t-nuts",
  "t-slot-corner-brackets",
  "t-slot-extrusions",
  "2020-extrusion",
  "button-head-screws-metric"
 ],
 "fits": [
  {
   "role": "Goes in or on",
   "items": [
    {
     "slug": "t-slot-extrusions",
     "why": "passes the slot opening, turns 90° in the cavity"
    }
   ]
  },
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "button-head-screws-metric",
     "why": "screw into the tap-drill hole"
    }
   ]
  },
  {
   "role": "Alternatives",
   "items": [
    {
     "slug": "slide-in-t-nuts",
     "why": "full-width nut slid in from the end"
    }
   ]
  }
 ],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. 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.",
 "mating": [
  {
   "feature": "T-nut tongue",
   "exact": "slot opening × lip (6.0 × 1.8 on 20-series; 8.0 on 30/40; 6.5 on 10-series)",
   "mates": "slot opening",
   "fit": "slide",
   "files": "tnut-"
  },
  {
   "feature": "drop-in T-nut width",
   "exact": "slot opening",
   "mates": "passes through the opening",
   "fit": "slide",
   "files": "tnut-dropin-"
  },
  {
   "feature": "drop-in T-nut length",
   "exact": "cavity − 1",
   "mates": "turns 90° in the cavity",
   "fit": "designed",
   "files": "tnut-dropin-"
  },
  {
   "feature": "T-nut thread hole",
   "exact": "tap drill (M3 2.5 … M8 6.8, 1/4-20 5.1, 10-32 4.0)",
   "mates": "screw thread",
   "fit": "designed",
   "files": "tnut-"
  },
  {
   "feature": "bracket / gusset / plate screw holes",
   "exact": "Ø5.5 / 6.6 / 9.0 / 7.14",
   "mates": "M5 / M6 / M8 / 1/4-20 clearance",
   "fit": "designed",
   "files": "all"
  }
 ],
 "fit_classes": {
  "press": "stays put: pin, tube, bearing or magnet held by interference. Typical FDM: hole +0.0 to +0.1 mm on diameter.",
  "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. Typical FDM: +0.2 mm.",
  "run": "turns or slides in use: pin in a link, rod through a guide. Typical FDM: +0.3 mm.",
  "socket": "large sliding fit: syringe barrel, sleeve, bobbin in a bore. Typical FDM: +0.3 mm.",
  "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 a drop-in T-nut for 2020?",
   "a": "A 10 × 6 × 4.2 mm nut that passes the 6 mm opening and turns 90° in the 11 mm cavity."
  },
  {
   "q": "Why is the drop-in nut 1 mm shorter than the cavity?",
   "a": "So it can rotate 90° inside the slot; it is a designed gap."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "tnut-dropin-20-m3",
   "formats": [
    "step",
    "stl"
   ],
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   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/tnut-dropin-20-m3.step",
   "stl": "https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/tnut-dropin-20-m3.stl",
   "note": "drop-in T-nut, 20-series slot: 10 × 6 × 4.2 body, 6 tongue (exact to the opening), M3 tap-drill hole Ø2.5"
  },
  {
   "file": "tnut-dropin-20-m4",
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   "stl": "https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/tnut-dropin-20-m4.stl",
   "note": "drop-in T-nut, 20-series slot: 10 × 6 × 4.2 body, 6 tongue (exact to the opening), M4 tap-drill hole Ø3.3"
  },
  {
   "file": "tnut-dropin-20-m5",
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   "stl": "https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/tnut-dropin-20-m5.stl",
   "note": "drop-in T-nut, 20-series slot: 10 × 6 × 4.2 body, 6 tongue (exact to the opening), M5 tap-drill hole Ø4.2"
  },
  {
   "file": "tnut-dropin-30-m5",
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   "stl": "https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/tnut-dropin-30-m5.stl",
   "note": "drop-in T-nut, 30-series slot: 15.5 × 8 × 6 body, 8 tongue (exact to the opening), M5 tap-drill hole Ø4.2"
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  {
   "file": "tnut-dropin-30-m6",
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   "stl": "https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/tnut-dropin-30-m6.stl",
   "note": "drop-in T-nut, 30-series slot: 15.5 × 8 × 6 body, 8 tongue (exact to the opening), M6 tap-drill hole Ø5"
  },
  {
   "file": "tnut-dropin-30-m8",
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   "stl": "https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/tnut-dropin-30-m8.stl",
   "note": "drop-in T-nut, 30-series slot: 15.5 × 8 × 6 body, 8 tongue (exact to the opening), M8 tap-drill hole Ø6.8"
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  {
   "file": "tnut-dropin-40-m6",
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   "stl": "https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/tnut-dropin-40-m6.stl",
   "note": "drop-in T-nut, 40-series slot: 19 × 8 × 6.5 body, 8 tongue (exact to the opening), M6 tap-drill hole Ø5"
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   "stl": "https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/tnut-dropin-40-m8.stl",
   "note": "drop-in T-nut, 40-series slot: 19 × 8 × 6.5 body, 8 tongue (exact to the opening), M8 tap-drill hole Ø6.8"
  },
  {
   "file": "tnut-dropin-10in-1-4-20",
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    "step",
    "stl"
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   "stl": "https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/tnut-dropin-10in-1-4-20.stl",
   "note": "drop-in T-nut, 10in-series slot: 13.4 × 6.5 × 4.8 body, 6.5 tongue (exact to the opening), 1/4-20 tap-drill hole Ø5.1"
  },
  {
   "file": "tnut-dropin-10in-10-32",
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    "step",
    "stl"
   ],
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   "stl": "https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/tnut-dropin-10in-10-32.stl",
   "note": "drop-in T-nut, 10in-series slot: 13.4 × 6.5 × 4.8 body, 6.5 tongue (exact to the opening), 10-32 tap-drill hole Ø4"
  }
 ],
 "markdown": "https://xemstudio.com/objects/drop-in-t-nuts/index.md"
}