/* [Flange Dimensions] */
outer_diameter = 80; // [20:1:200]
thickness = 6; // [1:0.5:30]
central_bore_diameter = 30; // [1:0.5:150]
bolt_hole_diameter = 8; // [1:0.5:30]
bolt_hole_count = 4; // [1:1:24]
pitch_circle_diameter = 60; // [10:1:180]
bolt_pattern_offset = 45; // [0:1:360]

/* [Appearance] */
plate_color = "Silver"; // color

/* [Hidden] */
$fn = 128;

// Nominal dimensions in millimeters; bottom at Z=0.
module through_hole(hole_diameter) {
    translate([0, 0, -1])
        cylinder(d=hole_diameter, h=thickness + 2);
}

module flange_plate() {
    difference() {
        cylinder(d=outer_diameter, h=thickness);
        through_hole(central_bore_diameter);
        for (hole_index = [0:bolt_hole_count - 1]) {
            rotate([0, 0, bolt_pattern_offset + hole_index * 360 / bolt_hole_count])
                translate([pitch_circle_diameter / 2, 0, 0])
                    through_hole(bolt_hole_diameter);
        }
    }
}

color(plate_color) flange_plate();