ORIGINAL: ghoffman
I got them at Lowe's, right next to the plastic ones in the electrical department! You can only tighten them so much, nowhere near like a worm gear hose clamp.
Stop being so difficult!
I think you will eventually need the buttonhead screws. Mine seemed to hold well at first, but eventually there was some slippage. Another annoying little job, but once done the problem is well and truly resolved.