Review on Hillman Group 230018 Screw Pieces by Richard Cuneo

I'm inserting shelves into wooden 2x4 (behind drywall). The shelf measures 8 feet by 2 feet so is fairly stable with large brackets. Revain "recommended" these 1/4 x 2-1/4 screws. The first or second broke - the upper parts of the thread were torn off (see figure). I just raised her up a bit, didn't play Hulk. Just after it stopped turning "slightly" another 1/4 turn had to be made to tighten. Snap.OK, maybe a bad one? But still, I expected to replace them all. I had to finish, so I completed the installation, being careful not to tighten it past initial resistance. Coming to the last one, I might have tightened up a bit at the end (still a long way from the Hulk). Click. So two. Go to the big box.