As I’ve been putting my machine together, the BOM calls for M3 x 15 screws. From my 3D printer experience, 14mm and 15mm lengths are fairly rare (you can get them on mcmaster, but not at hardware stores usually) and they come at a price premium. I’d suggest editing this to 16mm screws, as there are only a couple spots the screws stick out and they are harmless. This could save some people a couple dollars, and possibly frustration.