{
 "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": "print-in-place-ratchet-flexible-pawl",
 "name": "Print-in-place: ratchet with flexible pawls (12 teeth, one-way)",
 "kind": "hardware",
 "category": "3D printing",
 "group": "Print-in-place mechanisms",
 "year": null,
 "question": "How do you 3D print a working ratchet (one-way clutch) in one piece?",
 "tags": [
  "3d printable",
  "print in place",
  "no assembly",
  "no supports",
  "mechanism",
  "stl",
  "step",
  "ratchet",
  "compliant mechanism"
 ],
 "aliases": [
  "print in place ratchet",
  "3d printed ratchet mechanism",
  "one way clutch print in place",
  "ratchet and pawl stl",
  "compliant ratchet"
 ],
 "overall_mm": {
  "length": 76,
  "width": 76,
  "height": 28
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 3,
 "url": "https://xemstudio.com/objects/print-in-place-ratchet-flexible-pawl/",
 "sheet_txt": "https://xemstudio.com/objects/print-in-place-ratchet-flexible-pawl/sheet.txt",
 "sheet": {
  "basis": "Xem Studio design: internal ratchet teeth, compliant pawl arms, 45° V-groove bearing; one designed running gap of 0.40 mm",
  "overall_mm": {
   "length": 76,
   "width": 76,
   "height": 28
  },
  "notes": [
   "3D print in place — prints already assembled, moving, in one job. Drawn at true size with no printer tolerance added; the 0.40 mm running gaps are part of the design.",
   "Running gap 0.40 mm per side, 0.80 mm on diameter — part of the design, drawn as is. On the 45° faces the same 0.40 mm is measured square to the face (0.57 mm along the axis).",
   "Bed: flat. The frame ring and the wheel both stand on the bed; in the bottom 6 mm layer the frame carries 12 internal ratchet teeth and the wheel two thin arms whose tips sit in tooth spaces, 0.40 mm clear.",
   "Support while printing: above the teeth the frame closes inward as a 45° cone over the arms (0.40 mm square to the arm tips' top corners) and then wraps the wheel's raised boss with a 45° V-ridge in a V-groove; the boss and knob are plain cylinders. Nothing overhangs more than 45°.",
   "Captured: the V-ridge in the boss's V-groove holds the wheel up and down; the boss runs in the ridge with 0.40 mm all round.",
   "Freeing it: hold the frame and turn the knob in the free direction one full turn (12 clicks); flex each arm once with a fingertip through the top if it feels stuck.",
   "Motion: free direction — continuous, the arm tips ride up the 3 mm ramps (bending 3.1 mm inward) and drop off each locking face: 12 clicks per turn. Locking direction — it turns 0.77° until a pawl tip meets a tooth face, then stops (computed)."
  ],
  "table": {
   "columns": [
    "key",
    "value",
    "what"
   ],
   "rows": [
    [
     "gap_mm",
     0.4,
     "running gap per side on every moving interface (radial, axial, under captured parts) — part of the design, not a tolerance"
    ],
    [
     "frame_od_mm",
     76,
     ""
    ],
    [
     "teeth",
     12,
     "internal ratchet teeth (radial locking face, straight ramp)"
    ],
    [
     "tooth_depth_mm",
     3,
     "root Ø60, tip Ø54"
    ],
    [
     "pawls",
     2,
     "flexible arms on the wheel, 180° apart (both engage)"
    ],
    [
     "pawl_arm_mm",
     "1.6 wide × 100° of arc",
     "on Ø51.5"
    ],
    [
     "pawl_flex_mm",
     3.06,
     "arm-tip travel inward to pass a tooth"
    ],
    [
     "lock_play_deg",
     0.77,
     "free turn in the locking direction before a pawl meets a tooth face"
    ],
    [
     "clicks_per_turn",
     12,
     "free direction"
    ],
    [
     "knob_d_mm",
     43.48,
     "wheel boss / knob"
    ],
    [
     "axial_play_mm",
     0.57,
     ""
    ],
    [
     "height_mm",
     28.03,
     "as printed"
    ],
    [
     "mount_holes",
     "3 × Ø3.4",
     "frame"
    ]
   ]
  }
 },
 "sheet_text": "Print-in-place: ratchet with flexible pawls (12 teeth, one-way) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/print-in-place-ratchet-flexible-pawl/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\nBasis: Xem Studio design: internal ratchet teeth, compliant pawl arms, 45° V-groove bearing; one designed running gap of 0.40 mm\nCatalog version: 2026-10-20\n\nOverall (mm): length 76.0, width 76.0, height 28.0\n- 3D print in place — prints already assembled, moving, in one job. Drawn at true size with no printer tolerance added; the 0.40 mm running gaps are part of the design.\n- Running gap 0.40 mm per side, 0.80 mm on diameter — part of the design, drawn as is. On the 45° faces the same 0.40 mm is measured square to the face (0.57 mm along the axis).\n- Bed: flat. The frame ring and the wheel both stand on the bed; in the bottom 6 mm layer the frame carries 12 internal ratchet teeth and the wheel two thin arms whose tips sit in tooth spaces, 0.40 mm clear.\n- Support while printing: above the teeth the frame closes inward as a 45° cone over the arms (0.40 mm square to the arm tips' top corners) and then wraps the wheel's raised boss with a 45° V-ridge in a V-groove; the boss and knob are plain cylinders. Nothing overhangs more than 45°.\n- Captured: the V-ridge in the boss's V-groove holds the wheel up and down; the boss runs in the ridge with 0.40 mm all round.\n- Freeing it: hold the frame and turn the knob in the free direction one full turn (12 clicks); flex each arm once with a fingertip through the top if it feels stuck.\n- Motion: free direction — continuous, the arm tips ride up the 3 mm ramps (bending 3.1 mm inward) and drop off each locking face: 12 clicks per turn. Locking direction — it turns 0.77° until a pawl tip meets a tooth face, then stops (computed).\n\nkey  value  what\ngap_mm  0.4  running gap per side on every moving interface (radial, axial, under captured parts) — part of the design, not a tolerance\nframe_od_mm  76.0  \nteeth  12  internal ratchet teeth (radial locking face, straight ramp)\ntooth_depth_mm  3.0  root Ø60, tip Ø54\npawls  2  flexible arms on the wheel, 180° apart (both engage)\npawl_arm_mm  1.6 wide × 100° of arc  on Ø51.5\npawl_flex_mm  3.06  arm-tip travel inward to pass a tooth\nlock_play_deg  0.77  free turn in the locking direction before a pawl meets a tooth face\nclicks_per_turn  12  free direction\nknob_d_mm  43.48  wheel boss / knob\naxial_play_mm  0.57  \nheight_mm  28.03  as printed\nmount_holes  3 × Ø3.4  frame\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Xem Studio: Print-in-place mechanism design (geometry computed in the generator) — web — Xem Studio design — https://xemstudio.com/\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 3 parts): https://xemstudio.com/files/hardware/print-in-place-ratchet-flexible-pawl/index.json\nAPI: https://xemstudio.com/api/geometry?object=print-in-place-ratchet-flexible-pawl\n",
 "sources": [
  {
   "publisher": "Xem Studio",
   "title": "Print-in-place mechanism design (geometry computed in the generator)",
   "url": "https://xemstudio.com/",
   "formats": [
    "web"
   ],
   "license": "Xem Studio design",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "print-in-place-captive-wheel-axle",
  "print-in-place-barrel-hinge-180",
  "print-in-place-multi-knuckle-hinge",
  "print-in-place-captive-turntable",
  "print-in-place-dovetail-slider",
  "print-in-place-articulated-chain",
  "print-in-place-ball-joint"
 ],
 "fits": [],
 "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": [],
 "faq": [
  {
   "q": "Which part flexes?",
   "a": "The two pawls are thin arms (1.6 mm wide, 100° of arc) cut into the wheel; a 3.2 mm slot behind each lets it bend inward over the teeth."
  },
  {
   "q": "How much backlash does it have?",
   "a": "0.77° in the locking direction — the 0.40 mm gap between pawl tip and tooth face, seen from the axis."
  }
 ],
 "files_license": {
  "name": "Xem Studio Design License",
  "holder": "Xem Studio",
  "url": "https://xemstudio.com/license/",
  "note": "Xem Studio's own design: free to use, print, modify and sell things made from it; not to be republished or redistributed as files."
 },
 "offers": [
  {
   "file": "print-in-place-ratchet-flexible-pawl-assembly",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/print-in-place-ratchet-flexible-pawl/print-in-place-ratchet-flexible-pawl-assembly.step",
   "stl": "https://xemstudio.com/files/hardware/print-in-place-ratchet-flexible-pawl/print-in-place-ratchet-flexible-pawl-assembly.stl",
   "note": "The whole print as laid on the bed (2 bodies, already assembled); STEP keeps each moving body a separate solid"
  },
  {
   "file": "print-in-place-ratchet-flexible-pawl-frame",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/print-in-place-ratchet-flexible-pawl/print-in-place-ratchet-flexible-pawl-frame.step",
   "stl": "https://xemstudio.com/files/hardware/print-in-place-ratchet-flexible-pawl/print-in-place-ratchet-flexible-pawl-frame.stl",
   "note": "Frame ring Ø76 with 12 internal teeth, 45° cone and V-ridge bearing, 3 × Ø3.4"
  },
  {
   "file": "print-in-place-ratchet-flexible-pawl-wheel",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/print-in-place-ratchet-flexible-pawl/print-in-place-ratchet-flexible-pawl-wheel.step",
   "stl": "https://xemstudio.com/files/hardware/print-in-place-ratchet-flexible-pawl/print-in-place-ratchet-flexible-pawl-wheel.stl",
   "note": "Wheel with two flexible pawl arms, boss with 45° V-groove, knob with pointer slot"
  }
 ],
 "markdown": "https://xemstudio.com/objects/print-in-place-ratchet-flexible-pawl/index.md"
}