deskthority

I'm designing a custom keyboard. I plan on a sandwich construction and aluminum as the material. I'm curious what type/size screws others have used in their boards and the size of the pilot holes for the screws.

Any insight is appreciated.

Somewhere around M3 is popular, but you can use any size really. For the size of the pilot holes just look up clearance hole sizes for the screw you decide on.

M3 is one of those sizes that you can find screws and tools for anywhere ... except maybe in the US.
I often use a 2.5mm drill bit for the pilot hole and a one-step tap and a simple tapping handle. There are also three-step taps that supposedly produce threads of higher quality but they are harder to come by and expensive.

Do also check which lengths of screws that are available before you design the screw holes. I messed up on that when building a keyboard and had to cut the tips off with a Dremel.

Thanks

Findecanor wrote: M3 is one of those sizes that you can find screws and tools for anywhere ... except maybe in the US.
I often use a 2.5mm drill bit for the pilot hole and a one-step tap and a simple tapping handle. There are also three-step taps that supposedly produce threads of higher quality but they are harder to come by and expensive.

Do also check which lengths of screws that are available before you design the screw holes. I messed up on that when building a keyboard and had to cut the tips off with a Dremel.

Do you tap each piece individually or tap them sandwiched together. I've never used a tap before

If I understand your question correctly, you should only have to tap the bottom layer.