They are made to scale (7)

I believe the answer is:

ladders

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'they' is the definition.
Both the answer and definition are plural nouns.
Perhaps you can see a link between them that I don't see?

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for ladders that I've seen before include "lots of steps" , "Rows of rungs" , "Stocking snags" , "Hose runners" , "Climbing devices" .)

I've seen this clue in The Globe and Mail.

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