I know most people shield their guitars but I have built 6 and have never shielded any and now none of them make noise. I had a cheap strat and got a Laney LX12 cheap amp as a kit and had nothing but hum. Replaced amp with a Fender Mustang and Line 6 Spider and replaced cheap pups with some Fender noiseless and it doesnt hum. I make my own cables as I find some are very noisy and make sure all my earths are good. When I finish the build I just plug in to an amp and put my hands on strings and bridge to make sure the earth is good. I have built 3 single coiled guitars and none of them hum so maybe I am lucky.