// Parametric Flange based on engineering drawing
// All dimensions in millimeters (mm)

/* [Main Dimensions] */
// Outer diameter of the flange
outer_diameter = 80; // [40:1:200]

// Central bore diameter
bore_diameter = 30; // [10:1:150]

// Thickness of the flange plate
flange_thickness = 6; // [2:1:50]

/* [Bolt Hole Pattern] */
// Pitch Circle Diameter (P.C.D.) of bolt holes
pcd = 60; // [20:1:180]

// Number of bolt holes
hole_count = 4; // [1:1:24]

// Diameter of bolt holes
hole_diameter = 8; // [2:0.5:20]

// Rotational offset angle of bolt hole pattern (degrees)
hole_angle_offset = 45; // [0:5:180]

/* [Appearance] */
part_color = "LightSlateGray";

/* [Rendering Quality] */
$fn = 120;

module flange() {
    difference() {
        // Outer cylindrical body
        cylinder(d = outer_diameter, h = flange_thickness, center = true);

        // Center through-hole
        cylinder(d = bore_diameter, h = flange_thickness + 2, center = true);

        // Bolt holes array on Pitch Circle Diameter (P.C.D.)
        for (i = [0 : hole_count - 1]) {
            angle = hole_angle_offset + i * (360 / hole_count);
            rotate([0, 0, angle])
                translate([pcd / 2, 0, 0])
                    cylinder(d = hole_diameter, h = flange_thickness + 2, center = true);
        }
    }
}

color(part_color) {
    flange();
}