I designed this staircase with spacers between the tread and the stringer. Metal spacers in this size and quantity would have cost more than the timber, so I used black nylon spacers with metallic paint.

It is very solid and doesn’t creak, possibly because I used massive 100mm M10 coach screws.

This will do for now, but I would like to add a few sci-fi touches, like accent lighting and custom rubber treads.