// 1U is 44.45mm
// the wood plates are ~3mm
h = 44.45 - 6;

// using 1/2" #8 wood screws, we want a pilot hole through
// the PLA spacer. I'm not sure if the pilot hole should be
// treated as a softwood or hardwood size. Experiment and
// find out.
// d_soft is definitely too narrow
// d_hard was too narrow as well.
// 3.5mm was still too narrow. I'm going to switch to 2.5mm
// and try using a M2.5 machine screw, since I have a tap
d_next = 2.5;
d_hard = 3.175;
d_soft = 2.38252;
d_outer = 10;

plate = true;

difference () {
    if (plate) {
         translate([2, 2, 1]) {
             cube([16, 16, 2], center = true);
         };
         
    }
    cylinder(h, d = d_outer, $fn = 360);
    cylinder(h, d = d_next, $fn = 360);
};