{
 "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": "barrel-cam-mechanism",
 "name": "Barrel (cylindrical) cam with pin follower",
 "kind": "hardware",
 "category": "Mechanisms",
 "group": "Cams",
 "year": null,
 "question": "How does a barrel cam make reciprocating motion?",
 "tags": [
  "mechanism",
  "cams",
  "kinematics"
 ],
 "aliases": [
  "barrel cam",
  "cylindrical cam",
  "groove cam",
  "drum cam"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/barrel-cam-mechanism/",
 "sheet_txt": "https://xemstudio.com/objects/barrel-cam-mechanism/sheet.txt",
 "sheet": {
  "basis": "Xem Studio drawing; classic mechanism (Brown No. 106)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A groove cut round a cylinder carries a follower pin: one turn moves the pin along the axis by the groove's rise and back. Here a sine groove gives 15 mm of simple-harmonic stroke.",
   "Groove shape sets the motion: a helix reversed at the ends gives uniform speed (Brown's grooved cylinder), a sine gives smooth harmonic motion.",
   "Used in sewing machines, fishing reels' level wind and indexing tables.",
   "Parts (each has its own page): barrel-cam-r20-h15, dowel-pins-metric. Brown's movement No. 106 shows it (1868)."
  ],
  "table": {
   "columns": [
    "parameter",
    "value"
   ],
   "rows": [
    [
     "cylinder",
     "Ø40 × 50 mm"
    ],
    [
     "stroke",
     "15 mm"
    ],
    [
     "groove width",
     "6.4 mm (Ø6 pin)"
    ]
   ]
  }
 },
 "sheet_text": "Barrel (cylindrical) cam with pin follower — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/barrel-cam-mechanism/  (CC BY 4.0)\nBasis: Xem Studio drawing; classic mechanism (Brown No. 106)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A groove cut round a cylinder carries a follower pin: one turn moves the pin along the axis by the groove's rise and back. Here a sine groove gives 15 mm of simple-harmonic stroke.\n- Groove shape sets the motion: a helix reversed at the ends gives uniform speed (Brown's grooved cylinder), a sine gives smooth harmonic motion.\n- Used in sewing machines, fishing reels' level wind and indexing tables.\n- Parts (each has its own page): barrel-cam-r20-h15, dowel-pins-metric. Brown's movement No. 106 shows it (1868).\n\nparameter  value\ncylinder  Ø40 × 50 mm\nstroke  15 mm\ngroove width  6.4 mm (Ø6 pin)\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Henry T. Brown (1868, public domain): Five Hundred and Seven Mechanical Movements — scan on archive.org — web — Publisher's page; dimensions are facts — https://archive.org/details/fivehundredseven00browiala\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/barrel-cam-mechanism/index.json\nAPI: https://xemstudio.com/api/geometry?object=barrel-cam-mechanism\n",
 "sources": [
  {
   "publisher": "Henry T. Brown (1868, public domain)",
   "title": "Five Hundred and Seven Mechanical Movements — scan on archive.org",
   "url": "https://archive.org/details/fivehundredseven00browiala",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "barrel-cam-r20-h15",
  "dowel-pins-metric"
 ],
 "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": "How does a barrel cam make reciprocating motion?",
   "a": "A groove cut round a cylinder carries a follower pin: one turn moves the pin along the axis by the groove's rise and back. Here a sine groove gives 15 mm of simple-harmonic stroke."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "barrel-cam-mechanism-assembly",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/barrel-cam-mechanism/barrel-cam-mechanism-assembly.step",
   "stl": "https://xemstudio.com/files/hardware/barrel-cam-mechanism/barrel-cam-mechanism-assembly.stl",
   "note": "Assembled mechanism, all parts placed (STEP keeps each part separate)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/barrel-cam-mechanism/index.md"
}