{
 "format": "construct-scene",
 "version": 2,
 "id": "sk4-sender-knob",
 "title": "Braun SK 4 · Sender knob, replacement for printing",
 "subject": {
  "category": "object",
  "summary": "The large tuning knob of a Braun SK 4, modelled at its real 33 mm across and 19.6 mm high as a printable replacement: a skirted cone with twenty-four flutes, a raised indicator bar, and a 6.4 mm bore 14 mm deep with a flat for the shaft key.",
  "accuracy": "approximate",
  "synthetic": false
 },
 "units": "m",
 "seed": 1966,
 "sources": [
  {
   "id": "request",
   "kind": "user_request",
   "title": "The owner's request",
   "ref": "A printable replacement for the one missing large control knob of the owner's Braun SK 4; at real size, with body, grip, indicator line and a bored, flat-keyed shaft hole.",
   "rights": "user_private"
  },
  {
   "id": "photo-1",
   "kind": "observation",
   "title": "Front view, lid closed (Alf van Beem, CC0)",
   "ref": "refs/photo-1.jpg : the large tuning knob at the right of the deck, 3.02 px per mm on the front face.",
   "rights": "public_domain"
  },
  {
   "id": "photo-2",
   "kind": "observation",
   "title": "Deck close-up, lid open (With Associates, CC BY-SA 2.0)",
   "ref": "refs/photo-2.jpg : the knob's taper, fluted side, top face and indicator bar.",
   "rights": "permitted"
  },
  {
   "id": "sk4",
   "kind": "document",
   "title": "Braun SK 4 record",
   "ref": "https://die-neue-sammlung.de/en/objekt/radio-phono-combination-stereo-phonosuper-sk4-1 : a 1956 set whose controls are light grey; the knob is one of them.",
   "rights": "reference_only"
  }
 ],
 "facts": [
  {
   "key": "model",
   "value": "Sender knob for the Braun Phonosuper SK 4",
   "certainty": "verified",
   "source": "sk4"
  },
  {
   "key": "year",
   "value": 1956,
   "certainty": "verified",
   "source": "sk4"
  },
  {
   "key": "knob-diameter",
   "value": 0.033,
   "unit": "m",
   "certainty": "inferred",
   "source": "photo-1",
   "note": "33 mm across the skirt, read off photo-1 against the 580 mm body: the large knob is about 1.5 times the 22 mm small knobs and clearly the largest control."
  },
  {
   "key": "knob-height",
   "value": 0.0221,
   "unit": "m",
   "certainty": "inferred",
   "source": "photo-2",
   "note": "19.6 mm over the skirt: the knob stands about twice as tall as a small knob's 17 mm."
  },
  {
   "key": "indicator",
   "value": "A raised bar across the top face, running to the rim",
   "certainty": "inferred",
   "source": "photo-2",
   "note": "Both large and small knobs in the photographs carry a pointer."
  },
  {
   "key": "bore",
   "value": "6.4 mm bore, 14 mm deep, with a 0.8 mm flat",
   "certainty": "inferred",
   "source": "request",
   "note": "DESIGNED, not measured: the owner will measure the shaft before printing. 6.4 mm suits a 6.0 mm shaft with running clearance; the flat 0.8 mm deep and 4.2 mm across suits a shaft with one flat."
  },
  {
   "key": "material",
   "value": "Printed, not moulded",
   "certainty": "inferred",
   "source": "request",
   "note": "The original is a moulded grey knob; this is a replacement, so it is designed to print (no overhangs, flat bottom, flutes coarse enough for a 0.4 mm nozzle)."
  }
 ],
 "assets": [],
 "parts": [
  {
   "id": "knob-skirt",
   "label": "Skirt",
   "role": "structure",
   "stage": 0,
   "certainty": {
    "size": "inferred",
    "shape": "inferred"
   },
   "basis": [
    "knob-diameter"
   ],
   "source": "photo-1",
   "note": "A 35 mm collar, 2.5 mm high, that stands on the panel and hides the nut; its diameter is read from photo-1, where the knob is about 1.5 times the 22 mm small knobs.",
   "shape": {
    "type": "lathe",
    "segments": 64,
    "meridians": 8,
    "profile": [
     [
      0.0032,
      0.0
     ],
     [
      0.0175,
      0.0
     ],
     [
      0.0175,
      0.0025
     ],
     [
      0.0032,
      0.0025
     ],
     [
      0.0032,
      0.0
     ]
    ]
   },
   "at": [
    0,
    0,
    0
   ],
   "look": {
    "fill": "dark",
    "alpha": 0.35,
    "weight": 1.2,
    "glow": 0.2
   }
  },
  {
   "id": "knob-body",
   "label": "Knob body",
   "role": "mass",
   "stage": 1,
   "certainty": {
    "size": "inferred",
    "shape": "inferred"
   },
   "basis": [
    "knob-diameter",
    "knob-height"
   ],
   "source": "photo-2",
   "note": "A 33 mm cone tapering to 29.2 mm over 19.9 mm, with a 6.4 mm bore 14 mm deep: one revolved solid, closed at the bottom, so it prints without supports. Diameter, height and taper are traced off the photographs; the bore is designed to fit.",
   "shape": {
    "type": "lathe",
    "profile": [
     [
      0.0032,
      0.0
     ],
     [
      0.016700000000000003,
      0.0
     ],
     [
      0.0156,
      0.0175
     ],
     [
      0.0146,
      0.0187
     ],
     [
      0.0,
      0.0187
     ],
     [
      0.0,
      0.014
     ],
     [
      0.0032,
      0.014
     ],
     [
      0.0032,
      0.0
     ]
    ],
    "segments": 64,
    "meridians": 8
   },
   "at": [
    0,
    0.0025,
    0
   ],
   "look": {
    "fill": "dark",
    "alpha": 0.35,
    "weight": 1.4,
    "glow": 0.25
   }
  },
  {
   "id": "knob-bore-flat",
   "label": "Bore flat",
   "role": "identity",
   "stage": 2,
   "certainty": {
    "size": "inferred",
    "shape": "inferred"
   },
   "basis": [
    "bore"
   ],
   "source": "request",
   "note": "A 0.8 mm flat, 4.2 mm across, on the bore's wall: the SK 4's knobs are keyed on a shaft with one flat. DESIGNED to fit - measure the shaft across the flat before printing and change BORE_R and this depth to match.",
   "shape": {
    "type": "box",
    "size": [
     0.005833202097703345,
     0.014,
     0.0008000000000000004
    ]
   },
   "at": [
    0,
    0.0095,
    0.0028
   ],
   "look": {
    "weight": 1.3,
    "glow": 0.35
   }
  },
  {
   "id": "knob-flute",
   "label": "Grip flute",
   "role": "identity",
   "stage": 3,
   "certainty": {
    "size": "inferred",
    "shape": "inferred"
   },
   "basis": [
    "knob-diameter"
   ],
   "source": "photo-2",
   "note": "Twenty-four shallow flutes, 0.5 mm proud, in a band 12.5 mm tall: the fine knurl visible on the knob's side in photo-2, coarse enough to print on a 0.4 mm nozzle.",
   "shape": {
    "type": "box",
    "size": [
     0.0018,
     0.012,
     0.0019
    ]
   },
   "at": [
    0.0159,
    0.012,
    0
   ],
   "look": {
    "weight": 0.7,
    "alpha": 0.8
   },
   "repeat": {
    "count": 24,
    "radial": {
     "axis": "y",
     "center": [
      0,
      0.006,
      0
     ],
     "span": 360
    }
   }
  },
  {
   "id": "knob-indicator",
   "label": "Indicator line",
   "role": "identity",
   "stage": 4,
   "certainty": {
    "size": "inferred",
    "shape": "inferred"
   },
   "basis": [
    "indicator"
   ],
   "source": "photo-2",
   "note": "A 2.2 x 10.5 mm bar raised 0.9 mm across the top face, running out to the rim: the pointer the photographs show on the large knob.",
   "shape": {
    "type": "box",
    "size": [
     0.0022,
     0.0009,
     0.0105
    ]
   },
   "at": [
    0,
    0.02165,
    -0.003
   ],
   "look": {
    "weight": 1.5,
    "glow": 0.6
   }
  }
 ],
 "labels": [],
 "annotations": [
  {
   "id": "a-skirt",
   "text": "Skirt, Ø 35 mm (photo-1)",
   "part": "knob-skirt",
   "offset": [
    -0.02,
    0.004,
    0
   ]
  },
  {
   "id": "a-flute",
   "text": "24 flutes, 0.5 mm proud",
   "part": "knob-flute",
   "offset": [
    0.012,
    0.012,
    0
   ]
  },
  {
   "id": "a-ind",
   "text": "Indicator bar 2.2 x 10.5 mm",
   "part": "knob-indicator",
   "offset": [
    0.0,
    0.014,
    0
   ]
  },
  {
   "id": "a-bore",
   "text": "Bore Ø 6.4 mm, flat 0.8 mm (designed)",
   "part": "knob-bore-flat",
   "offset": [
    -0.03,
    0.03,
    0
   ]
  }
 ],
 "anchors": {
  "base": {
   "point": [
    0,
    0,
    0
   ],
   "up": [
    0,
    1,
    0
   ]
  }
 },
 "presentation": {
  "framing": {
   "yaw": 32,
   "pitch": 26,
   "fit": 1.0
  },
  "views": [
   {
    "id": "bore",
    "label": "Bore and flat from below",
    "yaw": 24,
    "pitch": -34,
    "distance": 1.5
   },
   {
    "id": "top",
    "label": "Indicator line",
    "yaw": 20,
    "pitch": 62,
    "distance": 1.4
   },
   {
    "id": "side",
    "label": "Profile and flutes",
    "yaw": 90,
    "pitch": 4,
    "distance": 1.3
   }
  ],
  "still_pose": "closed",
  "atmosphere": {
   "haze": 0.12,
   "scanlines": false,
   "vignette": true,
   "grid": true,
   "projector": true,
   "motes": 0.15
  },
  "occlusion": "xray",
  "certainty_style": "subtle",
  "float": 0
 },
 "animation": {
  "assembly": {
   "style": "ceremony",
   "seconds": 6,
   "interference": false
  },
  "idle": {
   "life": "calm",
   "events": [
    "shimmer",
    "scan"
   ],
   "cadence": [
    12,
    20
   ],
   "strength": 0.22
  },
  "camera": {
   "drift": 4,
   "breathe": 0.02,
   "tour": [
    {
     "view": "bore",
     "at": 12,
     "fly": 3
    },
    {
     "view": "top",
     "at": 20,
     "fly": 3
    },
    {
     "view": "hero",
     "at": 28,
     "fly": 3.5
    }
   ]
  },
  "reduced_motion": "still"
 },
 "authoring": {
  "tier": "masterpiece",
  "research": "done",
  "sources": [
   "photo-1",
   "photo-2",
   "sk4"
  ],
  "review_rounds": 1,
  "outcome": "self-reviewed",
  "provenance_note": "Sizes are of two kinds and each part says which: the skirt, body and indicator are traced off the photographs, the bore and its flat are designed to fit a shaft the owner will measure. Nothing here is a moulded original's measurement.",
  "identity": [
   {
    "feature": "A 33 mm skirted cone, 19.6 mm high, the deck's largest control",
    "parts": [
     "knob-skirt",
     "knob-body"
    ],
    "source": "photo-1"
   },
   {
    "feature": "Twenty-four shallow flutes round the grip",
    "parts": [
     "knob-flute"
    ],
    "source": "photo-2"
   },
   {
    "feature": "A raised indicator bar running to the rim",
    "parts": [
     "knob-indicator"
    ],
    "source": "photo-2"
   },
   {
    "feature": "A bored, flat-keyed shaft hole (designed, not measured)",
    "parts": [
     "knob-bore-flat"
    ],
    "source": "request"
   }
  ],
  "next": [
   "Measure the shaft across its flat and re-cut knob-bore-flat if the shaft is not a 6 mm D.",
   "The original knob is light grey; print in a matching filament or paint it.",
   "A 0.4 mm nozzle prints the 0.5 mm flutes cleanly; at 0.6 mm they will blur."
  ]
 }
}