// Mechanical Flange to Drawing Specifications
// All dimensions in millimeters (mm)

/* [Flange Dimensions] */
// Outer diameter of the flange
outer_diameter = 80;        // [30:1:200]

// Center bore diameter
inner_diameter = 30;        // [10:1:150]

// Total thickness of the flange
flange_thickness = 6;       // [1:0.5:50]

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

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

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

// Angular offset of first hole (45° for symmetrical 4-hole pattern as drawn)
hole_angle_offset = 45;     // [0:1:360]

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

/* [Detail] */
$fn = 120;

module flange() {
    color(flange_color)
    difference() {
        // Main flange disc
        cylinder(d = outer_diameter, h = flange_thickness, center = true);

        // Center through-bore
        cylinder(d = inner_diameter, h = flange_thickness + 1, center = true);

        // Bolt through-holes on P.C.D.
        if (hole_count > 0) {
            for (i = [0 : hole_count - 1]) {
                angle = hole_angle_offset + i * (360 / hole_count);
                translate([
                    (pcd / 2) * cos(angle),
                    (pcd / 2) * sin(angle),
                    0
                ])
                cylinder(d = hole_diameter, h = flange_thickness + 1, center = true);
            }
        }
    }
}

flange();