[BGood]

For USA made humbuckers, Imperial thread.

 

[BGood]

They appear to be magnetic also, the one on the right is oriented North up

Ever seen metric screws with slotted heads ?

 

[BGood]

Slotted screws create the best tones, as long as the slots are oriented the right way.

Tone sluts ?

 

[BGood]

Flat head screwdriver versions are also common for butterfly wall fasteners.

Maybe if you live in the USA. I think I'd have to ask for a custom order at my hardware store to get slotted head screws. They went the way of the rotary dial phone and 8 track cassettes.