{
 "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": "plastic-thread-forming-screw-holes",
 "name": "Thread-forming screws for plastic (EJOT PT type): screw hole diameter by plastic, M2.2–M4, boss hole rule, K sizes",
 "kind": "standard",
 "category": "Hardware",
 "group": "Fasteners",
 "year": null,
 "question": "What hole diameter does a PT thread-forming screw need in ABS, nylon, polycarbonate or polypropylene?",
 "tags": [
  "plastic screw",
  "pt screw",
  "thread forming screw plastic",
  "ejot pt",
  "delta pt",
  "boss hole",
  "plastic boss",
  "screw for abs",
  "fastener",
  "tool"
 ],
 "aliases": [
  "screw hole size abs m3",
  "pt screw hole diameter",
  "m3 screw boss hole abs",
  "thread forming screw for plastic hole size",
  "polycarbonate m3 screw pilot hole",
  "nylon screw boss hole diameter",
  "ejot pt screw hole",
  "ejot delta pt",
  "m2.5 pt screw hole",
  "plastic boss screw hole 0.8 d",
  "pp screw boss hole m4",
  "self tapping screw plastic pilot hole"
 ],
 "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/plastic-thread-forming-screw-holes/",
 "sheet_txt": "https://xemstudio.com/objects/plastic-thread-forming-screw-holes/sheet.txt",
 "sheet": {
  "basis": "EJOT's PT flyer (nominal diameters, hole rule, lengths) and a maker sheet of PT hole diameters by plastic, M2.2 to M4; numbers only",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "The hole table gives the recommended hole diameter in mm by plastic for M2.2, M2.5, M3, M3.5 and M4 PT-type screws, standard materials one row each. The sheet lists the high-strength group (glass-filled PA / PBT, PC, PC-GF30, PMMA, PPO, PEEK, PPS) with one value set; the layout did not show whether each material has its own values, so it is shown as one row (it matches the ABS row). For materials with high filler content or high internal strength the same sheet says the optimum hole diameter can be increased to 0.88 d, where d is the nominal screw diameter.",
   "EJOT's flyer prints the rule hole diameter dh = 0.7 to 0.8 × d1 depending on the material (d1 the nominal screw diameter); the table values equal 0.7 × d for PE-LD / PP, 0.75 × d for PA, POM, PE-HD, PBT, PET and 0.8 × d for ABS, PS, PVC and the glass-filled grades. The flyer also prints other design ratios (for example dT = 2 × d1, 0.3 to 0.5 × d1 and di = 2 × d1 near the drawing), but the text read did not say which dimension each belongs to, so they are not stated here. Boss outside diameter and engagement depth tables by PT size were not in the sources read (EJOT refers to its design recommendation or hotline).",
   "EJOT PT sizes by K designation (nominal diameter, mm): K10 1, K12 1.2, K14 1.4, K16 1.6, K18 1.8, K20 2, K22 2.2, K25 2.5, K30 3, K35 3.5, K40 4, K50 5, K60 6, K70 7, K80 8, K100 10. Screw lengths (mm, with the flyer's tolerance): 3, 3.5, 4, 4.5, 5, 6, 7, 8, 10, 12, 14, 16, 18, 20, 22, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100 (which lengths exist for which diameter is not clear from the text read). EJOT recommends DELTA PT for high-filler or high-strength materials and, to reduce boss shear stress when assembling, first reducing the outside boss diameter and then increasing the hole diameter (a larger hole lowers pull-out load; deeper engagement can offset it).",
   "Not on this page: other makers' screws for plastic (Stanley Plastite, PT-K families by other brands) and ASME Type B / AB plastic hole sizes (the hole tables read were not usable). No file: a PT thread (30° flank, trilobular-like profile) is not drawn from numbers here.",
   "Heat-set inserts for plastic bosses: heat-set-insert-holes; sheet metal pilot holes: sheet-metal-screw-pilot-holes."
  ],
  "table": {
   "columns": [
    "group",
    "plastic",
    "M2.2 hole (mm)",
    "M2.5 hole (mm)",
    "M3 hole (mm)",
    "M3.5 hole (mm)",
    "M4 hole (mm)"
   ],
   "rows": [
    [
     "standard materials",
     "ABS",
     "1.76",
     "2",
     "2.4",
     "2.8",
     "3.2"
    ],
    [
     "standard materials",
     "ABS/PC blend (incl. regrind)",
     "1.76",
     "2",
     "2.4",
     "2.8",
     "3.2"
    ],
    [
     "standard materials",
     "ASA",
     "1.716",
     "1.95",
     "2.34",
     "2.73",
     "3.12"
    ],
    [
     "standard materials",
     "PA 4.6",
     "1.606",
     "1.825",
     "2.19",
     "2.555",
     "2.92"
    ],
    [
     "standard materials",
     "PA 6",
     "1.65",
     "1.875",
     "2.25",
     "2.625",
     "3"
    ],
    [
     "standard materials",
     "PA 6.6",
     "1.65",
     "1.875",
     "2.25",
     "2.625",
     "3"
    ],
    [
     "standard materials",
     "PBT",
     "1.65",
     "1.875",
     "2.25",
     "2.625",
     "3"
    ],
    [
     "standard materials",
     "PE-LD",
     "1.54",
     "1.75",
     "2.1",
     "2.45",
     "2.8"
    ],
    [
     "standard materials",
     "PE-HD",
     "1.65",
     "1.875",
     "2.25",
     "2.625",
     "3"
    ],
    [
     "standard materials",
     "PET",
     "1.65",
     "1.875",
     "2.25",
     "2.625",
     "3"
    ],
    [
     "standard materials",
     "PET-GF30",
     "1.76",
     "2",
     "2.4",
     "2.8",
     "3.2"
    ],
    [
     "standard materials",
     "POM",
     "1.65",
     "1.875",
     "2.25",
     "2.625",
     "3"
    ],
    [
     "standard materials",
     "POM-GF30",
     "1.76",
     "2",
     "2.4",
     "2.8",
     "3.2"
    ],
    [
     "standard materials",
     "PP",
     "1.54",
     "1.75",
     "2.1",
     "2.45",
     "2.8"
    ],
    [
     "standard materials",
     "PP-GF30",
     "1.584",
     "1.8",
     "2.16",
     "2.52",
     "2.88"
    ],
    [
     "standard materials",
     "PP-TV20 (20% reclaimed)",
     "1.584",
     "1.8",
     "2.16",
     "2.52",
     "2.88"
    ],
    [
     "standard materials",
     "PS",
     "1.76",
     "2",
     "2.4",
     "2.8",
     "3.2"
    ],
    [
     "standard materials",
     "PVC",
     "1.76",
     "2",
     "2.4",
     "2.8",
     "3.2"
    ],
    [
     "standard materials",
     "SAN",
     "1.694",
     "1.925",
     "2.31",
     "2.695",
     "3.08"
    ],
    [
     "high-strength group (as read: one value set for the whole group)",
     "PA 4.6-GF30, PA 6-GF30, PA 6.6-GF30, PBT-GF30, PC, PC-GF30, PMMA, PPO, PEEK, PPS",
     "1.76",
     "2",
     "2.4",
     "2.8",
     "3.2"
    ]
   ]
  }
 },
 "sheet_text": "Thread-forming screws for plastic (EJOT PT type): screw hole diameter by plastic, M2.2–M4, boss hole rule, K sizes — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/plastic-thread-forming-screw-holes/  (sheet CC BY 4.0)\nBasis: EJOT's PT flyer (nominal diameters, hole rule, lengths) and a maker sheet of PT hole diameters by plastic, M2.2 to M4; numbers only\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The hole table gives the recommended hole diameter in mm by plastic for M2.2, M2.5, M3, M3.5 and M4 PT-type screws, standard materials one row each. The sheet lists the high-strength group (glass-filled PA / PBT, PC, PC-GF30, PMMA, PPO, PEEK, PPS) with one value set; the layout did not show whether each material has its own values, so it is shown as one row (it matches the ABS row). For materials with high filler content or high internal strength the same sheet says the optimum hole diameter can be increased to 0.88 d, where d is the nominal screw diameter.\n- EJOT's flyer prints the rule hole diameter dh = 0.7 to 0.8 × d1 depending on the material (d1 the nominal screw diameter); the table values equal 0.7 × d for PE-LD / PP, 0.75 × d for PA, POM, PE-HD, PBT, PET and 0.8 × d for ABS, PS, PVC and the glass-filled grades. The flyer also prints other design ratios (for example dT = 2 × d1, 0.3 to 0.5 × d1 and di = 2 × d1 near the drawing), but the text read did not say which dimension each belongs to, so they are not stated here. Boss outside diameter and engagement depth tables by PT size were not in the sources read (EJOT refers to its design recommendation or hotline).\n- EJOT PT sizes by K designation (nominal diameter, mm): K10 1, K12 1.2, K14 1.4, K16 1.6, K18 1.8, K20 2, K22 2.2, K25 2.5, K30 3, K35 3.5, K40 4, K50 5, K60 6, K70 7, K80 8, K100 10. Screw lengths (mm, with the flyer's tolerance): 3, 3.5, 4, 4.5, 5, 6, 7, 8, 10, 12, 14, 16, 18, 20, 22, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100 (which lengths exist for which diameter is not clear from the text read). EJOT recommends DELTA PT for high-filler or high-strength materials and, to reduce boss shear stress when assembling, first reducing the outside boss diameter and then increasing the hole diameter (a larger hole lowers pull-out load; deeper engagement can offset it).\n- Not on this page: other makers' screws for plastic (Stanley Plastite, PT-K families by other brands) and ASME Type B / AB plastic hole sizes (the hole tables read were not usable). No file: a PT thread (30° flank, trilobular-like profile) is not drawn from numbers here.\n- Heat-set inserts for plastic bosses: heat-set-insert-holes; sheet metal pilot holes: sheet-metal-screw-pilot-holes.\n\ngroup  plastic  M2.2 hole (mm)  M2.5 hole (mm)  M3 hole (mm)  M3.5 hole (mm)  M4 hole (mm)\nstandard materials  ABS  1.76  2  2.4  2.8  3.2\nstandard materials  ABS/PC blend (incl. regrind)  1.76  2  2.4  2.8  3.2\nstandard materials  ASA  1.716  1.95  2.34  2.73  3.12\nstandard materials  PA 4.6  1.606  1.825  2.19  2.555  2.92\nstandard materials  PA 6  1.65  1.875  2.25  2.625  3\nstandard materials  PA 6.6  1.65  1.875  2.25  2.625  3\nstandard materials  PBT  1.65  1.875  2.25  2.625  3\nstandard materials  PE-LD  1.54  1.75  2.1  2.45  2.8\nstandard materials  PE-HD  1.65  1.875  2.25  2.625  3\nstandard materials  PET  1.65  1.875  2.25  2.625  3\nstandard materials  PET-GF30  1.76  2  2.4  2.8  3.2\nstandard materials  POM  1.65  1.875  2.25  2.625  3\nstandard materials  POM-GF30  1.76  2  2.4  2.8  3.2\nstandard materials  PP  1.54  1.75  2.1  2.45  2.8\nstandard materials  PP-GF30  1.584  1.8  2.16  2.52  2.88\nstandard materials  PP-TV20 (20% reclaimed)  1.584  1.8  2.16  2.52  2.88\nstandard materials  PS  1.76  2  2.4  2.8  3.2\nstandard materials  PVC  1.76  2  2.4  2.8  3.2\nstandard materials  SAN  1.694  1.925  2.31  2.695  3.08\nhigh-strength group (as read: one value set for the whole group)  PA 4.6-GF30, PA 6-GF30, PA 6.6-GF30, PBT-GF30, PC, PC-GF30, PMMA, PPO, PEEK, PPS  1.76  2  2.4  2.8  3.2\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- EJOT: PT screw for thermoplastics (flyer 08.23): nominal diameters K10 to K100, hole diameter rule dh = 0.7 to 0.8 x d1, lengths 3 to 100 mm — web — Maker flyer; numbers only — https://www.ejot.de/medias/sys_master/Industry_Flyer/Industry_Flyer/h54/h3c/9331729760286/EJOT-PT-Flyer-08.23-en.pdf\n- Cold-forged fastener maker sheet (hosted on a Shopify CDN; PT hole sizes by plastic): Recommended hole diameter for PT-type screws by material, M2.2 to M4, standard and high-strength groups; note: high filler content up to 0.88 d — web — Maker datasheet; numbers only — https://cdn.shopify.com/s/files/1/0056/7856/3437/files/MetPTholesize.pdf\n- EJOT: PT screws for thermoplastics (product page; CAD and design recommendations on request) — web — Publisher's page; dimensions are facts — https://www.ejot.se/pt\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=plastic-thread-forming-screw-holes\n",
 "sources": [
  {
   "publisher": "EJOT",
   "title": "PT screw for thermoplastics (flyer 08.23): nominal diameters K10 to K100, hole diameter rule dh = 0.7 to 0.8 x d1, lengths 3 to 100 mm",
   "url": "https://www.ejot.de/medias/sys_master/Industry_Flyer/Industry_Flyer/h54/h3c/9331729760286/EJOT-PT-Flyer-08.23-en.pdf",
   "formats": [
    "web"
   ],
   "license": "Maker flyer; numbers only",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Cold-forged fastener maker sheet (hosted on a Shopify CDN; PT hole sizes by plastic)",
   "title": "Recommended hole diameter for PT-type screws by material, M2.2 to M4, standard and high-strength groups; note: high filler content up to 0.88 d",
   "url": "https://cdn.shopify.com/s/files/1/0056/7856/3437/files/MetPTholesize.pdf",
   "formats": [
    "web"
   ],
   "license": "Maker datasheet; numbers only",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "EJOT",
   "title": "PT screws for thermoplastics (product page; CAD and design recommendations on request)",
   "url": "https://www.ejot.se/pt",
   "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": [
  "heat-set-insert-holes",
  "heat-set-inserts",
  "sheet-metal-screw-pilot-holes",
  "self-tapping-screws-iso-7049-pan-head",
  "ribbed-plastic-expansion-anchors",
  "helical-thread-inserts-din-8140"
 ],
 "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": "boss hole",
   "exact": "M3 PT screw: 2.4 mm in ABS, 2.25 mm in PA 6 / POM / PBT, 2.1 mm in PP; rule 0.7 to 0.8 x d (up to 0.88 x d for filled / high-strength grades)",
   "mates": "EJOT PT-type thread-forming screw of the nominal diameter (M2.2 to M4 tabulated)",
   "fit": "designed",
   "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 hole for an M3 PT screw in ABS?",
   "a": "2.4 mm (0.8 × d); 2.25 mm in PA 6 / POM / PBT and 2.1 mm in PP and PE-LD, from the PT hole-size sheet."
  },
  {
   "q": "What is the hole rule for PT screws?",
   "a": "EJOT's flyer: hole diameter 0.7 to 0.8 × the nominal screw diameter depending on the material; up to 0.88 × d for high-filler or high-strength materials per the hole-size sheet."
  },
  {
   "q": "What does K30 mean on an EJOT PT screw?",
   "a": "K30 is the 3.0 mm nominal diameter (K25 is 2.5 mm, K40 4.0 mm)."
  }
 ],
 "files_license": null,
 "offers": [],
 "markdown": "https://xemstudio.com/objects/plastic-thread-forming-screw-holes/index.md"
}