bare/gpt-5.2-codex / tier-2-l-bracket

$fn = 64;

width = 50;
depth = 40;
height = 40;
thickness = 3;

hole_d = 4.5;
csk_d = 8;
csk_depth = 2;

difference() {
    union() {
        // Horizontal flange (X-Y plane, thickness in Z)
        cube([width, depth, thickness]);
        // Vertical flange (X-Z plane, thickness in Y)
        cube([width, thickness, height]);
    }

    // Holes on horizontal flange (countersink on top, z=thickness)
    for (y = [10, depth-10]) {
        translate([width/2, y, 0])
            cylinder(h = thickness, d = hole_d);
        translate([width/2, y, thickness - csk_depth])
            cylinder(h = csk_depth, d = csk_d);
    }

    // Holes on vertical flange (countersink on outer side, y=thickness)
    for (z = [10, height-10]) {
        translate([width/2, 0, z])
            rotate([90, 0, 0])
                cylinder(h = thickness, d = hole_d);
        translate([width/2, thickness - csk_depth, z])
            rotate([90, 0, 0])
                cylinder(h = csk_depth, d = csk_d);
    }
}