what i do is i will take a drill bit that is lager than the head of the screw and i drill into the side of the pipe. Then i use a bit that is the width of the threads and drill a hole on the bottom of the pipe, through the previous hole i drilled. Finally i use a screw driver NOT A DRILL to screw the screw in. A drill will crack the PVC, but with the screw driver make it tight. The hardest part is dropping the screw through the first hole and out the second, but if you get it it works like a charm. For a 10ft pipe, I use about 2 screws in the middle, one on each side, then 2 on each end (making 2 small holes through the ends of the pipe). Total of 6 screws for a 10ft PVC.
Wow that was a lot.