{
  "name": "SuperNX — engineering standards reference data",
  "url": "https://nxtolerance.com/data/index.json",
  "description": "Machine-readable tolerance-standards tables (ISO 286 limits & fits, ISO 2768-1 general tolerances, GD&T symbols) — the same data powering the free tools at nxtolerance.com/tools/.",
  "source": {
    "name": "Engineering tolerance standards reference data",
    "publisher": "SuperNX / nxtolerance.com",
    "standards": "ISO 286-1/-2 (limits & fits, IT grades), ISO 2768-1 (general tolerances), ASME Y14.5 symbol conventions",
    "note": "Values compiled from the published standard tables and cross-checked against multiple independent public references; see the verification log in the source repository."
  },
  "datasets": [
    {
      "id": "iso-286",
      "title": "ISO 286 limits & fits tables",
      "url": "https://nxtolerance.com/data/iso-286.json",
      "page": "https://nxtolerance.com/tools/",
      "description": "IT grades IT5–IT12 across 13 nominal size steps, plus shaft and hole fundamental deviations (µm) for the common letters."
    },
    {
      "id": "iso-2768",
      "title": "ISO 2768-1 general tolerances",
      "url": "https://nxtolerance.com/data/iso-2768.json",
      "page": "https://nxtolerance.com/tools/",
      "description": "Permissible deviations for linear dimensions and radii/chamfer heights, classes f / m / c / v (±mm)."
    },
    {
      "id": "gdt",
      "title": "GD&T characteristic symbols",
      "url": "https://nxtolerance.com/data/gdt.json",
      "page": "https://nxtolerance.com/tools/",
      "description": "The 14 ASME Y14.5 geometric tolerancing symbols — glyph, category, datum requirement and plain-English meaning."
    }
  ],
  "tools": [
    {
      "id": "iso-286-fit-calculator",
      "title": "ISO 286 Fit Calculator",
      "url": "https://nxtolerance.com/tools/iso-286-fit-calculator/",
      "description": "Hole and shaft limits, min/max clearance and fit type (clearance / transition / interference) for any nominal size — H7/g6, H7/p6, and the rest of the ISO 286 system."
    },
    {
      "id": "stack-up-calculator",
      "title": "Tolerance Stack-Up Calculator",
      "url": "https://nxtolerance.com/tools/stack-up-calculator/",
      "description": "Editable dimension chain with live worst-case (ΣT) and statistical (RSS, ≈±3σ) closing-gap results. Add parts, flip directions, see the gap breathe."
    }
  ],
  "disclaimer": "Engineering reference values for design and education — verify against the current standard revision (ISO 286-1:2010, ISO 2768-1:1989, ASME Y14.5) before issuing production drawings.",
  "license": "Standard reference data. Free to use and cite with attribution to nxtolerance.com.",
  "version": "2026-10-07"
}