{
 "meta": {
  "title": "Bolt Torque Chart",
  "rows": 21,
  "formula": {
   "preload": "F = 0.75 x Sp x At   (Sp = proof stress, not yield)",
   "torque": "T = K x D x F",
   "K": {
    "dry": 0.2,
    "zinc": 0.22,
    "lubricated": 0.15
   },
   "note": "K is a friction coefficient, not a physical constant. It varies with plating, lubricant, surface finish and reuse."
  },
  "strength_sources": [
   "SAE J429 proof stress (inch, Grade 2/5/8)",
   "ISO 898-1 proof stress (metric, classes 8.8 / 10.9 / 12.9)"
  ],
  "why_proof_not_yield": "Torque tables are built on proof load, the stress a bolt can take without measurable permanent set - not yield. Using yield strength instead overstates torque by roughly 8% in inch sizes and up to 20% in metric, which on a torque table is a safety error, not a rounding one.",
  "SCOPE_NOTICE": "General fastener torque only. This dataset deliberately contains NO vehicle-specific torque specifications (head bolts, oil pans, suspension, tightening sequences). Those are OEM service-manual data, vary by model year, and often require angle-torque or replace-once procedures that a table cannot express.",
  "lubrication_effect": "Going from dry (K=0.20) to lubricated (K=0.15) cuts required torque by 25% for the same preload. Applying a dry-spec torque to a lubricated bolt over-tightens it by about a third."
 },
 "columns": [
  "bolt",
  "grade",
  "system",
  "dry",
  "zinc_plated",
  "lubricated",
  "units"
 ],
 "rows": [
  {
   "bolt": "1/4-20",
   "grade": "Grade 2",
   "system": "inch",
   "dry": 5,
   "zinc_plated": 6,
   "lubricated": 4,
   "units": "lb-ft"
  },
  {
   "bolt": "1/4-20",
   "grade": "Grade 5",
   "system": "inch",
   "dry": 8,
   "zinc_plated": 9,
   "lubricated": 6,
   "units": "lb-ft"
  },
  {
   "bolt": "1/4-20",
   "grade": "Grade 8",
   "system": "inch",
   "dry": 12,
   "zinc_plated": 13,
   "lubricated": 9,
   "units": "lb-ft"
  },
  {
   "bolt": "5/16-18",
   "grade": "Grade 2",
   "system": "inch",
   "dry": 11,
   "zinc_plated": 12,
   "lubricated": 8,
   "units": "lb-ft"
  },
  {
   "bolt": "5/16-18",
   "grade": "Grade 5",
   "system": "inch",
   "dry": 17,
   "zinc_plated": 19,
   "lubricated": 13,
   "units": "lb-ft"
  },
  {
   "bolt": "5/16-18",
   "grade": "Grade 8",
   "system": "inch",
   "dry": 25,
   "zinc_plated": 27,
   "lubricated": 18,
   "units": "lb-ft"
  },
  {
   "bolt": "3/8-16",
   "grade": "Grade 2",
   "system": "inch",
   "dry": 20,
   "zinc_plated": 22,
   "lubricated": 15,
   "units": "lb-ft"
  },
  {
   "bolt": "3/8-16",
   "grade": "Grade 5",
   "system": "inch",
   "dry": 31,
   "zinc_plated": 34,
   "lubricated": 23,
   "units": "lb-ft"
  },
  {
   "bolt": "3/8-16",
   "grade": "Grade 8",
   "system": "inch",
   "dry": 44,
   "zinc_plated": 48,
   "lubricated": 33,
   "units": "lb-ft"
  },
  {
   "bolt": "7/16-14",
   "grade": "Grade 2",
   "system": "inch",
   "dry": 32,
   "zinc_plated": 35,
   "lubricated": 24,
   "units": "lb-ft"
  },
  {
   "bolt": "7/16-14",
   "grade": "Grade 5",
   "system": "inch",
   "dry": 49,
   "zinc_plated": 54,
   "lubricated": 37,
   "units": "lb-ft"
  },
  {
   "bolt": "7/16-14",
   "grade": "Grade 8",
   "system": "inch",
   "dry": 70,
   "zinc_plated": 77,
   "lubricated": 52,
   "units": "lb-ft"
  },
  {
   "bolt": "1/2-13",
   "grade": "Grade 2",
   "system": "inch",
   "dry": 49,
   "zinc_plated": 54,
   "lubricated": 37,
   "units": "lb-ft"
  },
  {
   "bolt": "1/2-13",
   "grade": "Grade 5",
   "system": "inch",
   "dry": 75,
   "zinc_plated": 83,
   "lubricated": 57,
   "units": "lb-ft"
  },
  {
   "bolt": "1/2-13",
   "grade": "Grade 8",
   "system": "inch",
   "dry": 106,
   "zinc_plated": 117,
   "lubricated": 80,
   "units": "lb-ft"
  },
  {
   "bolt": "9/16-12",
   "grade": "Grade 2",
   "system": "inch",
   "dry": 70,
   "zinc_plated": 77,
   "lubricated": 53,
   "units": "lb-ft"
  },
  {
   "bolt": "9/16-12",
   "grade": "Grade 5",
   "system": "inch",
   "dry": 109,
   "zinc_plated": 120,
   "lubricated": 82,
   "units": "lb-ft"
  },
  {
   "bolt": "9/16-12",
   "grade": "Grade 8",
   "system": "inch",
   "dry": 154,
   "zinc_plated": 169,
   "lubricated": 115,
   "units": "lb-ft"
  },
  {
   "bolt": "5/8-11",
   "grade": "Grade 2",
   "system": "inch",
   "dry": 97,
   "zinc_plated": 107,
   "lubricated": 73,
   "units": "lb-ft"
  },
  {
   "bolt": "5/8-11",
   "grade": "Grade 5",
   "system": "inch",
   "dry": 150,
   "zinc_plated": 165,
   "lubricated": 113,
   "units": "lb-ft"
  },
  {
   "bolt": "5/8-11",
   "grade": "Grade 8",
   "system": "inch",
   "dry": 212,
   "zinc_plated": 233,
   "lubricated": 159,
   "units": "lb-ft"
  },
  {
   "bolt": "3/4-10",
   "grade": "Grade 2",
   "system": "inch",
   "dry": 172,
   "zinc_plated": 190,
   "lubricated": 129,
   "units": "lb-ft"
  },
  {
   "bolt": "3/4-10",
   "grade": "Grade 5",
   "system": "inch",
   "dry": 267,
   "zinc_plated": 293,
   "lubricated": 200,
   "units": "lb-ft"
  },
  {
   "bolt": "3/4-10",
   "grade": "Grade 8",
   "system": "inch",
   "dry": 376,
   "zinc_plated": 414,
   "lubricated": 282,
   "units": "lb-ft"
  },
  {
   "bolt": "7/8-9",
   "grade": "Grade 2",
   "system": "inch",
   "dry": 167,
   "zinc_plated": 183,
   "lubricated": 125,
   "units": "lb-ft"
  },
  {
   "bolt": "7/8-9",
   "grade": "Grade 5",
   "system": "inch",
   "dry": 429,
   "zinc_plated": 472,
   "lubricated": 322,
   "units": "lb-ft"
  },
  {
   "bolt": "7/8-9",
   "grade": "Grade 8",
   "system": "inch",
   "dry": 606,
   "zinc_plated": 667,
   "lubricated": 455,
   "units": "lb-ft"
  },
  {
   "bolt": "1-8",
   "grade": "Grade 2",
   "system": "inch",
   "dry": 250,
   "zinc_plated": 275,
   "lubricated": 187,
   "units": "lb-ft"
  },
  {
   "bolt": "1-8",
   "grade": "Grade 5",
   "system": "inch",
   "dry": 644,
   "zinc_plated": 708,
   "lubricated": 483,
   "units": "lb-ft"
  },
  {
   "bolt": "1-8",
   "grade": "Grade 8",
   "system": "inch",
   "dry": 909,
   "zinc_plated": 999,
   "lubricated": 681,
   "units": "lb-ft"
  },
  {
   "bolt": "1-1/8-7",
   "grade": "Grade 2",
   "system": "inch",
   "dry": 354,
   "zinc_plated": 390,
   "lubricated": 266,
   "units": "lb-ft"
  },
  {
   "bolt": "1-1/8-7",
   "grade": "Grade 5",
   "system": "inch",
   "dry": 794,
   "zinc_plated": 874,
   "lubricated": 596,
   "units": "lb-ft"
  },
  {
   "bolt": "1-1/8-7",
   "grade": "Grade 8",
   "system": "inch",
   "dry": 1288,
   "zinc_plated": 1417,
   "lubricated": 966,
   "units": "lb-ft"
  },
  {
   "bolt": "1-1/4-7",
   "grade": "Grade 2",
   "system": "inch",
   "dry": 500,
   "zinc_plated": 550,
   "lubricated": 375,
   "units": "lb-ft"
  },
  {
   "bolt": "1-1/4-7",
   "grade": "Grade 5",
   "system": "inch",
   "dry": 1121,
   "zinc_plated": 1233,
   "lubricated": 840,
   "units": "lb-ft"
  },
  {
   "bolt": "1-1/4-7",
   "grade": "Grade 8",
   "system": "inch",
   "dry": 1817,
   "zinc_plated": 1999,
   "lubricated": 1363,
   "units": "lb-ft"
  },
  {
   "bolt": "M5\u00d70.8",
   "grade": "Class 8.8",
   "system": "metric",
   "dry": 6.2,
   "zinc_plated": 6.8,
   "lubricated": 4.6,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M5\u00d70.8",
   "grade": "Class 10.9",
   "system": "metric",
   "dry": 8.8,
   "zinc_plated": 9.7,
   "lubricated": 6.6,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M5\u00d70.8",
   "grade": "Class 12.9",
   "system": "metric",
   "dry": 10.3,
   "zinc_plated": 11.3,
   "lubricated": 7.7,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M6\u00d71",
   "grade": "Class 8.8",
   "system": "metric",
   "dry": 10.5,
   "zinc_plated": 11.6,
   "lubricated": 7.9,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M6\u00d71",
   "grade": "Class 10.9",
   "system": "metric",
   "dry": 15.0,
   "zinc_plated": 16.5,
   "lubricated": 11.3,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M6\u00d71",
   "grade": "Class 12.9",
   "system": "metric",
   "dry": 17.6,
   "zinc_plated": 19.3,
   "lubricated": 13.2,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M8\u00d71.25",
   "grade": "Class 8.8",
   "system": "metric",
   "dry": 25.5,
   "zinc_plated": 28.0,
   "lubricated": 19.1,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M8\u00d71.25",
   "grade": "Class 10.9",
   "system": "metric",
   "dry": 36.5,
   "zinc_plated": 40.1,
   "lubricated": 27.3,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M8\u00d71.25",
   "grade": "Class 12.9",
   "system": "metric",
   "dry": 42.6,
   "zinc_plated": 46.9,
   "lubricated": 32.0,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M10\u00d71.5",
   "grade": "Class 8.8",
   "system": "metric",
   "dry": 50.5,
   "zinc_plated": 55.5,
   "lubricated": 37.8,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M10\u00d71.5",
   "grade": "Class 10.9",
   "system": "metric",
   "dry": 72.2,
   "zinc_plated": 79.4,
   "lubricated": 54.1,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M10\u00d71.5",
   "grade": "Class 12.9",
   "system": "metric",
   "dry": 84.4,
   "zinc_plated": 92.8,
   "lubricated": 63.3,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M12\u00d71.75",
   "grade": "Class 8.8",
   "system": "metric",
   "dry": 88.0,
   "zinc_plated": 96.8,
   "lubricated": 66.0,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M12\u00d71.75",
   "grade": "Class 10.9",
   "system": "metric",
   "dry": 125.9,
   "zinc_plated": 138.5,
   "lubricated": 94.4,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M12\u00d71.75",
   "grade": "Class 12.9",
   "system": "metric",
   "dry": 147.1,
   "zinc_plated": 161.8,
   "lubricated": 110.3,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M14\u00d72",
   "grade": "Class 8.8",
   "system": "metric",
   "dry": 140.6,
   "zinc_plated": 154.7,
   "lubricated": 105.5,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M14\u00d72",
   "grade": "Class 10.9",
   "system": "metric",
   "dry": 201.2,
   "zinc_plated": 221.3,
   "lubricated": 150.9,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M14\u00d72",
   "grade": "Class 12.9",
   "system": "metric",
   "dry": 235.2,
   "zinc_plated": 258.7,
   "lubricated": 176.4,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M16\u00d72",
   "grade": "Class 8.8",
   "system": "metric",
   "dry": 218.1,
   "zinc_plated": 239.9,
   "lubricated": 163.6,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M16\u00d72",
   "grade": "Class 10.9",
   "system": "metric",
   "dry": 312.1,
   "zinc_plated": 343.3,
   "lubricated": 234.1,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M16\u00d72",
   "grade": "Class 12.9",
   "system": "metric",
   "dry": 364.7,
   "zinc_plated": 401.2,
   "lubricated": 273.5,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M20\u00d72.5",
   "grade": "Class 8.8",
   "system": "metric",
   "dry": 425.9,
   "zinc_plated": 468.5,
   "lubricated": 319.5,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M20\u00d72.5",
   "grade": "Class 10.9",
   "system": "metric",
   "dry": 609.5,
   "zinc_plated": 670.5,
   "lubricated": 457.2,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M20\u00d72.5",
   "grade": "Class 12.9",
   "system": "metric",
   "dry": 712.4,
   "zinc_plated": 783.6,
   "lubricated": 534.3,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M24\u00d73",
   "grade": "Class 8.8",
   "system": "metric",
   "dry": 736.0,
   "zinc_plated": 809.6,
   "lubricated": 552.0,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M24\u00d73",
   "grade": "Class 10.9",
   "system": "metric",
   "dry": 1053.3,
   "zinc_plated": 1158.6,
   "lubricated": 790.0,
   "units": "N\u00b7m"
  },
  {
   "bolt": "M24\u00d73",
   "grade": "Class 12.9",
   "system": "metric",
   "dry": 1230.9,
   "zinc_plated": 1354.0,
   "lubricated": 923.2,
   "units": "N\u00b7m"
  }
 ]
}