Under the seams of the hour, boys struggle in a dozen different arenas. Four hundred children crawling along the edge of a razor.
- From All the Light We Cannot See by Anthony Doerr
What does the seams of the hour mean here?
If we take the passage literally (as we must, since we do not interpret poetry here) ...
I would surmise that "the hour" is a reference to the academic "hour", and the "seams" refer (figuratively) to the time between classes when students move through the hallways of the school on to their next class. During this between-time they confront their individual existential dramas.
The difficult word is "under". Its literal sense may be an oblique reference to the clock that typically hangs high on the wall in school hallways. It is also associated with the domains of subjugation and oppression, which would be borne out by the words "struggle" and "crawl".
Sometimes writers use (invent) a metaphor that is not clear. This is one of those times. Unless you ask the author what he means, all we can do is try to figure it out, and this results in head scratching and guessing. If a metaphor's meaning is not apparent, then the author has failed to communicate. Maybe he doesn't care, but nonetheless he has.
Exactly how an hour has seams and what is meant by under these seams escapes my ability to decipher the author's meaning. Even the meaning of (the) hour is not clear. Hour has different meanings.
Perhaps he is alluding to some saying in an English other than American English. In that case the intended meaning might be clearer.