squint like a bag of nails

(idiomatic, obsolete, slang) To squint very much, as though one's eyes were directed as many ways as the points of a bag of nails.

Example: (quotations which may not support the sense given above:)
1947, Robert Briffault, New life of Mr. Martin:
  '[If you think] I'm going to find a billet for a good-for-nothing unclassed bollox, you're mighty mistaken,' said he, looking up at me for the first time, squinting like a bag of nails. 'This is a shipping office, not a refuge for stray dogs.'
1996, Alan Garner, Strandloper:
  "'Arrah,' says I, 'do you squint like a bag of nails, that you can't see a man before you?'"
  "And I says, 'Hold your mag, frig pig,'" said Renter [...]
2005, Mary Lancaster, An Endless Exile, page 21:
  In his own language, he called out, “Where is she then, Rob? Is she hideous? Does she squint like a bag of nails? Does she screech like a shrew with toothache?” This time, the silence was definitely appalled – not least, I suspected, because there was more than a grain of truth in Hereward's unflattering description.
2008, Georgette Heyer, Regency Buck, page 230:
  Does she squint like a bag of nails? Is she hideous? They always are!'
  The Earl stood back.'You may judge for yourself,' he said dryly. 'Miss Taverner, little though he may have recommended himself to you, I must beg leave to present my brother, Captain Audley.'