140 records

Is this DIN fastener interchangeable with its ISO equivalent?

140 records covering 16 DIN standards, one fact each. Every value is transcribed from the source that states it and carries the sentence it was taken from: 2 sources across 2 sites, last checked 2026-10-12, due for re-check by 2029-10-11. Every record is listed below, each linking the page its value came from.

Cite as: Sizes where a DIN fastener and its ISO equivalent are not interchangeable, referencesource.org/fastener-standard-interchangeability-exceptions/, checked 2026-10-12.

About this data

The specific thread sizes at which a withdrawn DIN fastener standard and its current ISO counterpart give DIFFERENT dimensions, so the two parts are not simply interchangeable. Each record is one size at which one named dimension differs between the two standards, with both published values side by side -- or, for two standard pairs, the publisher's own interchangeability verdict in its own words. Answers 'is DIN 933 the same as ISO 4017', 'DIN 934 vs ISO 4032 nut height', 'my drawing says DIN 931 and my distributor only stocks ISO 4014', and 'will my spanner still fit'. The headline DIN-to-ISO crossover mapping is easy, everyone publishes it, and it is NOT here: the sibling dataset fastener-thread-standard-equivalence owns that and states it from five publishers. What is here is the exception detail, where free sources fail and contradict each other. Wurth prints four sizes at which the width across flats changed between DIN 933 and ISO 4017 -- M10 17 mm becomes 16 mm, M12 19 becomes 18, M14 22 becomes 21, M22 32 becomes 34, meaning a different spanner -- while Monster Bolts lists that same pair as 'Fully interchangeable'. That disagreement is the fact, and it is published in full on the sibling's DIN 933 page, which carries both publishers' verdicts side by side and is linked from every page here. What this dataset adds is the sizes at which the blanket verdict fails. 16 standard pairs carry size-level divergences, across head diameter, head height, nut height, slot width and width across flats. Note that M22 goes UP, not down, so 'ISO is one size smaller' is a wrong rule of thumb.

The data

Where this came from

Every record above links the page it was taken from and quotes the sentence that states it. These are the 2 sources this dataset was assembled from.

• wurthindustry.cahttps://www.wurthindustry.ca/media/downloads/wic_pdfs/Fasteners_DIN-EN-ISO_Standards.pdf
• wuerth.dehttps://www.wuerth.de/web/de/awkg/kompetenz/din_iso_normteile/din-933-931-iso-4014-4017-sechskantschrauben.php

Machine-readable

• data.jsonThe whole dataset — every record with its source URL and source quote.
• Open Knowledge Format bundleOne JSON object per line — every record's frontmatter and quoted span exactly as it is held here, in one fetch.
• data.csvThe same records as one flat table, for a spreadsheet or a dataframe. The last four columns are the source URL, the quoted sentence it was read from, the date we last checked it, and which columns are our reading rather than the page's words.
• How this is made and checkedWhat "verified against source" does and does not mean.

From your own code

Same records, same quotes, without scraping the page: refsource is on PyPI and npm. Each value comes back carrying the URL it was read from and the sentence on that page that states it — .source and .quote sit on the value itself rather than in a side channel, so the checking step is available instead of skipped.

pip install refsource
refsource lookup fastener-standard-interchangeability-exceptions din_standard="DIN 85"

npx -y refsource lookup fastener-standard-interchangeability-exceptions din_standard="DIN 85"

Set your AI assistant up to use this

Two files and no account. Put this in .mcp.json at the root of your project — Claude Code, Cursor, Windsurf, VS Code and Codex all read that file — and your assistant can look this dataset up instead of recalling it. The server is remote, keyless and read-only.

{
  "mcpServers": {
    "referencesource": {
      "type": "http",
      "url": "https://referencesource.org/mcp"
    }
  }
}

Add to Cursor · or, on the command line: claude mcp add --transport http referencesource https://referencesource.org/mcp --scope project

Then one line in the project's CLAUDE.md or AGENTS.md, so the assistant knows when to reach for it:

When a question needs "Sizes where a DIN fastener and its ISO equivalent are not interchangeable", call the referencesource MCP server at https://referencesource.org/mcp (tool `search_records`, dataset_slug `fastener-standard-interchangeability-exceptions`) instead of answering from memory — every record it returns carries its source URL and a verbatim quote from that page.

What each tool does, and the servers built over single registers: Connect your AI assistant.

140 records. last verified against source 2026-10-12. due for re-check by 2029-10-11.

Licence. Facts extracted from freely published distributor technical pages. Dimensions are facts, not copyrightable expression (US: Feist, 1991). ISO 4017 and the other ISO fastener documents were not purchased or opened; ISO's own terms restrict use of ISO content, and no ISO content is used here -- only dimensions as facts, quoted from distributors who published them. Of Wurth Industry of Canada's booklet only the rows where two standards DIFFER were taken -- 134 rows out of several thousand cells printed -- so what is reproduced is the divergence, not the compilation. The Monster Bolts and TR Fastenings mapping rows were removed from this asset on 2026-10-16 as duplicates of fastener-thread-standard-equivalence; Monster Bolts' interchangeability verdict is quoted in the description and published in the sibling.