I live in an apartment building and am trying to put up a wall mounted pot rack in the drywall. I used a stud finder to locate the studs (16″ apart). Then I drilled some pilot holes and used #12 2 1/2″ wood screws to mount the pot rack. Two of the screws broke off when I was screwing them in – one using a power drill, one by hand. Am I overlooking something or doing it wrong? I’ve got very little experience with home improvement projects. Thanks!