I'm absolutely brand new here, just been searching for a solution to my problem.

I have a strat copy which I've been learning on for the past year, or rather relearning, as I was originally tutored right handed back in the 70's, but never felt comfortable as I'm naturally a lefty. so I'm starting again , left handed..! Anyway this copy has been great plays well, and no problems. So decided to treat myself and bought a s/h lefty Mexstrat, and being the person I am, I need to personalise, so decided to upgrade it by fitting new pickups, tremnut, Ernie Balls,give the frets a proper polish, and shield the cavity/pickguard with copper.
I took time over the choice of pickups, and after listening to numerous sound files eventually decided on Tonerider Classic Blues, easily the best sounding pickups I'd heard, with great revues. I've just completed the whole job, feeling really pleased with the whole thing, neat soldering, wiring and tidy shielding job, completed setting up of the action, string height intonation etc, everything seemed to be fine, except that while adjusting the pickup height, the screws on the neck pickup only, buzz when touched with the screwdriver..!! What have I done wrong? Should just say as well, I made sure there was good overlap with the copper at the top of the cavity with several tabs to screw holes, and the 3 pup ground wires were all soldered together on the same pot.