{
 "meta": {
  "dataset": "drills",
  "description": "Standard twist drill sizes (fractional, number, letter, metric).",
  "schema_version": "1",
  "generated": "2026-08-12",
  "records": 309,
  "license": "CC BY 4.0 — attribution: BenchReference (benchreference.com)",
  "sources": [
   "asme-b94-11m"
  ],
  "provenance": "https://benchreference.com/sources/"
 },
 "entries": [
  {
   "designation": "#80",
   "system": "number",
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   "mm": 0.3429
  },
  {
   "designation": "#79",
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   "inches": 0.0145,
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  },
  {
   "designation": "1/64″",
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  },
  {
   "designation": "#78",
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   "mm": 0.4064
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  {
   "designation": "#77",
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  },
  {
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  {
   "designation": "#75",
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  },
  {
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   "mm": 0.5714999999999999
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  {
   "designation": "#73",
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  },
  {
   "designation": "#72",
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   "mm": 0.635
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  {
   "designation": "#71",
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  },
  {
   "designation": "#70",
   "system": "number",
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  {
   "designation": "#69",
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  },
  {
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   "mm": 0.7874
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  {
   "designation": "1/32″",
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  {
   "designation": "#67",
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  {
   "designation": "#66",
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  {
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  {
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  {
   "designation": "1 mm",
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  {
   "designation": "#60",
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  {
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  {
   "designation": "#58",
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  {
   "designation": "1.1 mm",
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  {
   "designation": "#56",
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  {
   "designation": "1.2 mm",
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  {
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  {
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  {
   "designation": "#55",
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  {
   "designation": "#54",
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  {
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  {
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  {
   "designation": "#53",
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   "designation": "1/16″",
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  {
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  {
   "designation": "#52",
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  {
   "designation": "1.7 mm",
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   "designation": "#49",
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  {
   "designation": "2 mm",
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  {
   "designation": "2.05 mm",
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  {
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  {
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  {
   "designation": "#44",
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  },
  {
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  {
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  {
   "designation": "2.3 mm",
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  {
   "designation": "#42",
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  {
   "designation": "3/32″",
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  {
   "designation": "2.4 mm",
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  {
   "designation": "#41",
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  {
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  {
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  {
   "designation": "#39",
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  {
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  {
   "designation": "2.6 mm",
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  {
   "designation": "#37",
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  {
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  {
   "designation": "#36",
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  {
   "designation": "#35",
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  {
   "designation": "2.8 mm",
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  {
   "designation": "#34",
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  {
   "designation": "2.9 mm",
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  {
   "designation": "#32",
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  {
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  {
   "designation": "#31",
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   "designation": "3.1 mm",
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  {
   "designation": "3.2 mm",
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  },
  {
   "designation": "#30",
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  {
   "designation": "3.3 mm",
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  },
  {
   "designation": "3.4 mm",
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  },
  {
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  {
   "designation": "3.5 mm",
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  {
   "designation": "#28",
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  {
   "designation": "9/64″",
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   "mm": 3.571875
  },
  {
   "designation": "3.6 mm",
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  {
   "designation": "#27",
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   "designation": "3.7 mm",
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   "designation": "#26",
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  {
   "designation": "#24",
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  {
   "designation": "#23",
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  {
   "designation": "4 mm",
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  {
   "designation": "#21",
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  {
   "designation": "4.1 mm",
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  {
   "designation": "4.2 mm",
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   "designation": "#19",
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  {
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  {
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  {
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  {
   "designation": "#16",
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  {
   "designation": "4.5 mm",
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   "designation": "#14",
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   "mm": 4.699
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  {
   "designation": "4.7 mm",
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  {
   "designation": "3/16″",
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  {
   "designation": "4.8 mm",
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   "designation": "#12",
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   "designation": "#11",
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   "designation": "#10",
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  {
   "designation": "#9",
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  },
  {
   "designation": "5 mm",
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  {
   "designation": "#8",
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   "inches": 0.199,
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  },
  {
   "designation": "5.1 mm",
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  },
  {
   "designation": "#7",
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   "inches": 0.201,
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  {
   "designation": "13/64″",
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  {
   "designation": "#6",
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  {
   "designation": "5.2 mm",
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  },
  {
   "designation": "#5",
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   "mm": 5.2197
  },
  {
   "designation": "5.3 mm",
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   "mm": 5.3
  },
  {
   "designation": "#4",
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  {
   "designation": "5.4 mm",
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  {
   "designation": "#3",
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  },
  {
   "designation": "5.5 mm",
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  },
  {
   "designation": "7/32″",
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  {
   "designation": "5.6 mm",
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  },
  {
   "designation": "#2",
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   "mm": 5.6133999999999995
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  {
   "designation": "5.7 mm",
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   "mm": 5.7
  },
  {
   "designation": "#1",
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   "mm": 5.7912
  },
  {
   "designation": "5.8 mm",
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   "mm": 5.8
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  {
   "designation": "5.9 mm",
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   "mm": 5.9
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  {
   "designation": "A",
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  },
  {
   "designation": "15/64″",
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  },
  {
   "designation": "6 mm",
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   "mm": 6
  },
  {
   "designation": "B",
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   "mm": 6.0451999999999995
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  {
   "designation": "6.1 mm",
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  },
  {
   "designation": "C",
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   "mm": 6.1468
  },
  {
   "designation": "6.2 mm",
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   "mm": 6.2
  },
  {
   "designation": "D",
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   "mm": 6.248399999999999
  },
  {
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   "system": "fractional",
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   "mm": 24.209374999999998
  },
  {
   "designation": "31/32″",
   "system": "fractional",
   "inches": 0.96875,
   "mm": 24.60625
  },
  {
   "designation": "63/64″",
   "system": "fractional",
   "inches": 0.984375,
   "mm": 25.003124999999997
  },
  {
   "designation": "1″",
   "system": "fractional",
   "inches": 1,
   "mm": 25.4
  }
 ]
}