The problem, the work, and the answer.

The problem as it came in

The client bought a plant that had sat idle for years and wanted it running again. They had the original drawings, twenty years old, and 646 tags. For every tag: does this part still exist, who sells it, does it meet today's Canadian standards, and if not, what crossover will, and what work does that bring? Six tags came first, as the proof.

What had to be worked through

Finding a part is the easy half. The hard half is the chain of gates a listing has to pass before it can be trusted, and each one only opens if the one before it did.

1. The drawing gives the code. Without the plant's own order code there is nothing to compare against, so the record is built by hand from the drawing first.
2. The code unlocks the maker's table. Makers publish what every character of their code means. That table is typed in, character for character, never guessed.
3. The maker renamed the part. The drawing says one code and every seller says another. The record carries the new name, so the search finds what is really for sale.
4. The seller's title is read, not trusted. A search engine returns tennis racquets and toys with the same words in them. A listing only counts if the maker's name is in its title and the code inside it reads as a real code.
5. Each group of the code becomes a field. The approval mark, the signal, the thread, the range. Each is put beside the drawing and given one of four answers: Same, Different, Not stated, Stop.
6. A certificate is judged on what it is, not how it is spelt. An American mark in a Canadian area is a Stop. A Canadian mark written a different way is not.
7. Where the maker publishes no table, the tool says so. Three of the six makers do not. Every card on those parts says "Nothing checked" instead of guessing.
8. Money only counts what passed. The price box, the count on the front page and the sort all leave out anything the check refused, and say how many they left out.
9. The letter carries only what is safe to send. The supplier's message names the model and the duty. A guard refuses any tag, building or project number, every time.

What it does now

On the six proof tags: 291 listings from 65 sellers, and 71 of them ruled out in words a buyer can check. Five answers on every tag: does it still exist and where, what it costs, what condition it is in, how soon, and whether it will go in, and if not, what it would take. The engineer still signs. The tool makes sure nothing is hidden from them when they do. The other 640 tags run through the same machine.

The real one runs on a real plant with a different name. This copy is here so you can press it.